The used GStreamer codecs are picked using rank hierarchy. When there are 2 or more decoders available that can handle the same stream type, the one with higher rank is always picked. This commit adds a function for the codec rank manipulation that can be used for e.g. force disable/enable VAAPI. Should be a neat feature once we have a settings dialog where it can be used.
With this change Clapper can open and load a playlist inside a text file. The text file should have a ".claps" extension and include one media file path per line (path can be either absolute, relative or even a HTTP link).
