Fixes issues using DepsPath(32|64), was using ${lib_suffix} instead of
${_lib_suffix} so 32/64-sepcific directories wouldn't work properly.
Also the DepsPath environment/cmake variable wasn't specified for the
library search.
Also added the same dependency search paths for libfdk (if someone wants
to use it on windows for whatever reason)
This can make it a bit easier to set up 32bit/64bit environments
separately on windows. This simply allows you to additionally set
FFmpegPath32, FFmpegPath64, x264Path32, x264Path64, etc.