Fix bug in OneSixInstance's modification detection.

OneSixInstance would report all instances as custom because of a typo.
Thanks Clang :)
[Clang Warnings] Remove unused variables
[Clang Warnings] Fix char* cast from string literal in Tests
[Clang Warnings] Add empty default clause
[Clang Warnings] Silence Pack200 unused variable variable warnings

They're caused by a big define-everything-you-ever-need macro
Handle a bunch more clang warnings
Move settings lib into the main code, fixing error logging in it.