Using public headers where possible
qtbase v5.2.1 as submodule
Default to qtbase submodule
Merge remote-tracking branch 'hrobeers/master'

- Update .gitignore
- Add qtbase as submodule

I'm not accepting the change to smain.cpp because that file's just a patched
version of one from Qt, and messing with it unnecessarily will make merging
upstream changes more difficult in the future.
Add readme
Tidy up qtbase check slightly