Updated CHANGELOG with more details on breaking changes to poutput and perror

Also:
- Updated README with more info on a couple more open-source applications using cmd2

Author: tleonhardt

CHANGELOG.md

@@ -18,9 +18,12 @@
         * We make no API stability guarantees about these internal functions
     * Split `perror` into 2 functions:
         * `perror` - print a message to sys.stderr
-        * `pexcept` - print Exception message to sys.stderr. If debug is true, print exception traceback if one exists.
-    * Removed color parameters from `poutput` and `perror` since more powerful styles now exist. See the docstrings
-    of these methods for more information on applying styles to output messages.
+        * `pexcept` - print Exception message to sys.stderr. If debug is true, print exception traceback if one exists
+    * Signature of `poutput` and `perror` significantly changed
+        * Removed color parameters `color`, `err_color`, and `war_color` from `poutput` and `perror` 
+            * See the docstrings of these methods or the [cmd2 docs](https://cmd2.readthedocs.io/en/latest/unfreefeatures.html#poutput-pfeedback-perror-ppaged) for more info on applying styles to output messages
+        * `end` argument is now keyword-only and cannot be specified positionally
+        * `traceback_war` no longer exists as an argument since it isn't needed now that `perror` and `pexcept` exist
     * Moved `cmd2.Cmd.colors` to ansi.py and renamed it to `allow_ansi`. This is now an application-wide setting.
     * Renamed the following constants and moved them to ansi.py
         * `COLORS_ALWAYS` --> `ANSI_ALWAYS`

README.md

@@ -355,12 +355,16 @@ Here are a few examples of open-source projects which use `cmd2`:
     * [Ceph](https://ceph.com/) is a distributed object, block, and file storage platform
 * [JSShell](https://github.com/Den1al/JSShell)
     * An interactive multi-user web JavaScript shell
+* [psiTurk](https://psiturk.org)
+    * An open platform for science on Amazon Mechanical Turk
 * [Jok3r](http://www.jok3r-framework.com)
     * Network & Web Pentest Automation Framework
 * [Poseidon](https://github.com/CyberReboot/poseidon)
     * Leverages software-defined networks (SDNs) to acquire and then feed network traffic to a number of machine learning techniques
 * [Unipacker](https://github.com/unipacker/unipacker)
     * Automatic and platform-independent unpacker for Windows binaries based on emulation
+* [FLASHMINGO](https://github.com/fireeye/flashmingo)
+    * Automatic analysis of SWF files based on some heuristics. Extensible via plugins.
 * [tomcatmanager](https://github.com/tomcatmanager/tomcatmanager)
     * A command line tool and python library for managing a tomcat server
 * [mptcpanalyzer](https://github.com/teto/mptcpanalyzer)