Prepare for Python Packaging
Four main changes:
- Adds decoder handling functionality to libvid2frames rather than the executable. This means programs using the library do not have to implement handling of the decoder and files themselves.
 - Changes the CLI interface to accept an optional output directory, Argument parsers and usage advice are written for python and c interfaces with libvid2frames.
 - Removes DynAikonTrap dependency from python interface, allowing vid2frames to be packaged as a standalone python library dependant only on built 
libvid2frames.so - 
dynaikontrap-video.pyis renamed toVid2Frames.py, reflecting encapsulated python interface