Update README.

Added license and contributor text.

Author: thejpster

README.md

@@ -6,6 +6,7 @@ This is the Neotron OS. It will run on any system which can execute ARM Thumb v7
 
 This OS is a work in progress. We intend to support:
 
+* [x] Calling BIOS APIs
 * [ ] Text mode console (on both text and bitmap displays)
 * [ ] Starting a command-line shell application
 * [ ] Executing applications from RAM
@@ -14,3 +15,44 @@ This OS is a work in progress. We intend to support:
 * [ ] Music playback
 * [ ] Various keyboard layouts
 
+## Build Instructions
+
+```
+$ git clone https://github.com/neotron-compute/Neotron-OS.git
+$ cd Neotron-OS
+$ git submodule update --init
+$ nano ./Cargo.toml # Edit to use appropriate linker script
+$ cargo build --release
+$ cargo run --release # Fires up GDB to flash the board
+```
+
+## Changelog
+
+### Unreleased Changes ([Source](https://github.com/neotron-compute/Neotron-OS/tree/master))
+
+* Basic UART hello on start-up
+
+## Licence
+
+    Neotron-OS Copyright (c) The Neotron Developers, 2020
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+## Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally
+submitted for inclusion in the work by you shall be licensed as above, without
+any additional terms or conditions.
+
+