Docs: readme and contributing updates.

- Small improvement to Windows libusb install help, and removed note
  about the known issue that no longer applies.
- Replaced reference to Mbed contributing docs with License section.
- Added a short checklist under contributing Process.

Author: flit

CONTRIBUTING.md

@@ -14,11 +14,21 @@ Other formatting requirements:
 - 4 space indents, no tabs are allowed.
 - No trailing whitespace.
 - All source files must end with a newline (an empty line at the end).
-- Lines should generally not be longer than 120 characters, though this is not a hard rule.
+- Lines should generally not be longer than 120 characters, though this is not a hard rule. Overall readability
+  is more important.
 
 
 ## Process
 
+Before you submit your changes, please ensure that:
+
+- The code meets style requirements listed above.
+- You have added your copyright below existing copyrights in the files you modified. New files should have only
+  your copyright. See the License section below for more.
+- Changes have been tested locally to the extent possible. (Obviously, we don't expect you to have as many
+  test boards as we do.)
+- Your code works with both Python 2 and Python 3.
+
 Please create a pull request in GitHub with your contribution. Before creating the pull request,
 please ensure that all tests pass. We also run the tests on a wide range of boards for every pull
 request using our CI setup. Changes must pass on all tested boards before the the pull request can
@@ -29,8 +39,19 @@ environment. The [automated tests guide](docs/automated_tests.md) provides infor
 available types of tests and describes how to run the tests.
 
 
-## More
+## License
+
+By creating a pull request on GitHub, you are granting license your contributions under the same Apache 2.0
+license as the original code. However, the copyright on contributions is retained by their author(s). Please
+add your copyright below existing copyrights in the license header at the top of the source file. If you are
+doing the work for your employer, you should use your employer's copyright. If a file is newly added by you,
+it must contain the standard license header with your copyright. Please note that we do not list changes in
+each source file by copyright owner, as this becomes a burden to maintain.
+
+Contributing source code that is already licensed using a license other than Apache 2.0 is possible, but each
+case must be considered individually. (If you are the owner of the source code, then you have the right to
+relicense to Apache 2.0.) The most important thing is that the license is compatible with Apache 2.0. Examples
+are MIT, the BSD licenses, and similar. GPL-licensed code is expressly disallowed to be contributed, as the
+GPL is not compatible with Apache 2.0 (or any of the Apache-compatible licenses).
+
 
-For more information about contributing, see the Mbed OS [contributor
-documentation](http://os.mbed.com/contributing). Although this documentation is written primarily
-with Mbed OS in mind, much of it applies directly to pyOCD, as well.

README.md

@@ -10,7 +10,7 @@ API to enable low-level target control. A common use for the Python API is to ru
 tests.
 
 Upwards of 70 popular MCUs are supported built-in. In addition, through the use of CMSIS-Packs,
-nearly every Cortex-M device on the market is supported.
+[nearly every Cortex-M device](https://www.keil.com/dd2/pack/) on the market is supported.
 
 The `pyocd` command line tool gives you total control over your device with these subcommands:
 
@@ -22,6 +22,7 @@ The `pyocd` command line tool gives you total control over your device with thes
     that provide additional target device support.
 - `commander`: Interactive REPL control and inspection of the MCU.
 - `server`: Share a debug probe with a TCP/IP server.
+- `reset`: Hardware or software reset of a device.
 - `list`: Show connected devices.
 
 The API and tools provide these features:
@@ -143,12 +144,10 @@ How to install libusb depends on your OS:
 
 - macOS: use Homebrew: `brew install libusb`
 - Linux: should already be installed.
-- Windows: download libusb from [libusb.info](https://libusb.info/) and place the DLL in your Python
+- Windows: download libusb from [libusb.info](https://libusb.info/) and place the .dll file in your Python
   installation folder next to python.exe. Make sure to use the same 32- or 64-bit architecture as
-  your Python installation. *Note: due to a
-  [known issue](https://github.com/mbedmicro/pyOCD/issues/684), the current recommendation is to use
-  [libusb version 1.0.21](https://github.com/libusb/libusb/releases/tag/v1.0.21) on Windows instead
-  of the most recent version.*
+  your Python installation. The latest release is [available on GitHub](https://github.com/libusb/libusb/releases);
+  download the .7z archive under Assets. Use the library from the VS2019 folder in the archive.
 
 ### udev rules on Linux
 
@@ -227,7 +226,8 @@ Contributions
 -------------
 
 We welcome contributions to pyOCD in any area. Please see the [contribution
-guidelines](CONTRIBUTING.md) for detailed requirements for contributions.
+guidelines](CONTRIBUTING.md) for detailed requirements for contributions. In order foster a healthy
+and safe community, we expect contributors to follow the [code of conduct](CODE_OF_CONDUCT.md).
 
 To report bugs, please [create an issue](https://github.com/mbedmicro/pyOCD/issues/new) in the
 GitHub project.