Wrap up migration to github

Known issues remaining:

[x] Static information pages ( #2 ) e.g. Marketing, Tutorial, and Developer Engagement documents
[ ] Dynamic pages e.g. 'Live update checking' and bug reports. (https://github.com/openrocket/openrocket/issues/260)
[x] Hosting of Binaries ( #3 )
[ ] Build and DevOps- HTML Proofer CI with Travis
[ ] Coordinate the move of the Thesis ( #4 )

wcravens / openrocket