renderer: fix deadlock waiting to happen
[WIN32] load avformat via import library
[WIN32] load avcodec via import library
changed: call av_register_all() and avcodec_register_all() once. Is there probably a better place for it rather than Application.cpp?
[WIN32] load avfilter via import library
load avutil via the import library
load swresample via the import library.
load postproc via the import library
load swscale via the import library.
cleaning some unused vars and removed the ffmpeg libs from DllPaths.