SVN handles and Git names are merged into one person.
Perform keyboard layout switching whenever window focus is gained or lost.
Make layout switch duplicate guard bidirectional.
Refactor keyboard layout switching code into winbits.c and clean it up. No functional changes.
SDL 2.0.5
Update libpng to 1.6.25, built with GCC 6.2.
Fixes warning: type 'struct _SETJMP_FLOAT128' violates one definition rule [-Wodr]
Eliminate the need for separate manifests for 32-bit and 64-bit builds by specifying a wildcard for processorArchitecture attributes.
Remove OS version guard. Unsupported versions will fail to run in the first place due to missing symbol errors.
Re-add pre-XP version strings.
SDL 2.0.4
