OpenGL: Take cached viewport sub-rect into account for scissor

Fixes #1938

Qt: shutdown system if error on loading ROM

Fix clang-format lint

Add clang-format as part of our {commit,travis}-time checks

Travis: Fix OS X build

Probably due to additional Travis caching, cmake is now already
installed when the script runs. This causes the unlink to remove the
symlink to the executable, which is then not re-added by the install
(since it's already installed).

This makes clang-format useful on those.

Also add a bunch of forgotten transitive includes, which otherwise
prevented compilation.

VideoCore: Fix dangling lambda context in shader interpreter

The static meant that after the first execution, these lambda context
would be pointing to a random location on the stack. Fixes a random
crash when using the interpreter.

Interface ARM CPU JIT (Dynarmic)

Switch to readdir() from readdir_r()

Qt: fix birthday combo box updating