Build script

~~:exclamation: This is a work in progress, please do not pull / merged yet. Opening it now so you can see and comment on progress :) :exclamation:~~

Ready to go!

 Fixes #60

- [x] Clean up references
- [x] Initial build script to clean and compile solution
- [x] SharedAssemblyInfo and update version
- [x] ILRepack and internalize references
- [x] Create nuget packages

~~Run tests~~ lets skip this for now, can introduce to the build script in a separate bit of work.