hb-uniscribe.cc: Re-enable build under Visual Studio

-Declare hinstLib at the top of block
-Fix the definitions of the typedefs of ScriptItemizeOpenType,
 ScriptShapeOpenType and ScriptPlaceOpenType
Remove unnecessary stdint.h include
Fix build for C89 compilers
util/ansi-print.cc: Use fallback implementation for lround on MSVC

Unfortuately Visual Studio (still) does not support the C99 function
lround, so provide a fallback implementation for it.