* Turn on shaders optimization by default
Release builds of Filament only work well with optimize shaders,
turning optimizations on by default will help avoid mismatches.
This change also adds -g to disable all optimizations, for debug
builds.
* Use -g on debug builds
* Use -g on debug builds
* Update tutorial_redball.md to remove matc's -O
* Update tutorial_suzanne.md to remove matc's -O
* Use -g in debug builds
