WIP: FAKE it til you make it

This replaces the existing build scripts with a standalone FAKE script (and docs on how you can build/test NSubstitute locally).

- [x] version binaries
- [x] confirm &copy; renders correctly in `AssemblyInfo.cs`
- [x] clean and build
- [x] run tests
- [x] port logic for release notes
- [x] create package
- [x] create zip file containing binaries
- [x] generate docs site
- [x] generate and test code samples
- [ ] review and refine

### Usage

You can play with this right now.

`.\build` will build and run the test suite
`.\build Release` will build, run tests and create all the release artifacts