Add a number of bug-fixes to deal better with high res cams (#873434)
- Fix cheese-introduction.png being in both cheese and cheese-libs (#893756)
- Put the COPYING file in the docs for cheese-libs (#893800)
- Fix the flash when taking a photo being dark grey instead of white (#965813)
- Fix needing to press the effects button twice to select effects after
selecting an effect for the first time
- Various other bug-fixes