Autodetect "moc" commandline tool.
Updated detection to also support Qt5 (should fix #69).
Updated cmake script to use new filenames (fixes #74).
Added API to change the userdata of an image.
save PTS and userdata early so that it is valid in get_buffer()
only alloc output frames with custom alloc function
remember for each image which memory allocator is responsible
Merge pull request #81 from fancycode/cmake_fixes

Updated cmake script to use new filenames (fixes #74).
Merge pull request #80 from fancycode/detect_qtmoc_installation

Improve detection of "moc" tool / support Qt5
fix: also swap image allocation functions when swapping image memory
Merge pull request #82 from fancycode/set_image_userdata

Added API to change the userdata of an image.
Merge branch 'img-userdata'
remove debug output
check for null decctx