Fixed bug #33: The --fullscreen option doesn't work.
Merge branch 'develop' of github.com:mapmapteam/mapmap into develop
MediaImpl: move buffer processing in gstNewSampleCallback (bug #30)

Buffer releasing should happen independently of videoPull() getting called for
texture updates. We move all processing and buffer unreferencing in
gstNewSampleCallback. This way we don't run out of memory in case of video
pipeline playing without texture/mappings.
Removed commandline options for Qt < 5.0.0 (because it is not supported then).