Cleanup and Merges#15

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jmoyerman wants to merge 14 commits intoachimdoebler:masterfrom

jmoyerman:master

Commits on Feb 9, 2016

Wrap UG_FONT struct byte array access with macro in case an accessor
mattdf
committed

Commits on Feb 12, 2016

Commits on Feb 20, 2016

Add missing static function prototypes to make compiler happy.
AriZuu
committed

Commits on Mar 26, 2016

Images support 32bpp and 16 bpp now
jmoyerman
committed

Commits on Apr 23, 2016

Add const specifier for not changed variables.
Tobias Badertscher
committed

Commits on Apr 24, 2016