For future GFX channel functions an image scaling function is required.
This moves the implementation from wayland client to core library
and adds support for the much faster SWScale library.
found by cppcheck
[libfreerdp/codec/include/bitmap.c:112] -> [libfreerdp/codec/include/bitmap.c:95]: (warning) Either the condition '!pbSrcBuffer' is redundant or there is pointer arithmetic with NULL pointer.
[libfreerdp/codec/include/bitmap.c:112] -> [libfreerdp/codec/include/bitmap.c:96]: (warning) Either the condition '!pbDestBuffer' is redundant or there is pointer arithmetic with NULL pointer.
[client/X11/xf_floatbar.c:800] -> [client/X11/xf_floatbar.c:796]: (warning) Either the condition '!floatbar' is redundant or there is possible null pointer dereference: floatbar.
[client/X11/xf_floatbar.c:800] -> [client/X11/xf_floatbar.c:797]: (warning) Either the condition '!floatbar' is redundant or there is possible null pointer dereference: floatbar.
[client/X11/xf_floatbar.c:800] -> [client/X11/xf_floatbar.c:798]: (warning) Either the condition '!floatbar' is redundant or there is possible null pointer dereference: floatbar.
[libfreerdp/codec/dsp.c:1156] -> [libfreerdp/codec/dsp.c:1154]: (warning) Either the condition '!srcFormat' is redundant or there is possible null pointer dereference: srcFormat.
[channels/drdynvc/client/drdynvc_main.c:1453] -> [channels/drdynvc/client/drdynvc_main.c:1450]: (warning) Either the condition '!drdynvc' is redundant or there is possible null pointer dereference: drdynvc.
[channels/audin/client/opensles/audin_opensl_es.c:98] -> [channels/audin/client/opensles/audin_opensl_es.c:94]: (warning) Either the condition '!opensles' is redundant or there is possible null pointer dereference: opensles.
[channels/audin/client/opensles/audin_opensl_es.c:159] -> [channels/audin/client/opensles/audin_opensl_es.c:153]: (warning) Either the condition '!opensles' is redundant or there is possible null pointer dereference: opensles.
The spec doesn't require that FRAME_BEGIN, REGION, TILESET, and FRAME_END come all in one
chunk. This patch adds the necessary state saving.
A unitary test is also added.
