Semi-automatically taking the the misc-include-cleaner warnings
by clang-tidy and fixing files to be self-contained.
Change-Id: Iaaa2b2ec9d6dcce547fa5cb6b4f056dfc8c781ff
this provides better compatibility for older Visual Studio versions;
stdint.h is a part of C99.
this is consistent with the core libwebp library:
8fbb9188 prefer webp/types.h over stdint.h
Change-Id: I777cad70d9a407646c4193db9ca0f09e65d88735