raspberry pi additions

The solution didn't compile, project paths were broken and the packages folder wasn't ignored.
So I:

- Deleted packages from the repo and appended to gitignore
- Fixed the project paths
- Added solution folders for pi + compression demo

Solution still doesn't compile but it may be a little closer to doing so.
It might be an idea to let each talk have its own solution rather than make a mega solution as JK did for CompressionDemo