Updated technical documentation
Simplified and cleaned up design of frame server by packing all
information regarding streams in a struct and have one of these structs
for every opened stream.
Removed obsolete and broken test for frame number when switching
streams.
Implemented saving frames of matching frames of all streams to disk as
PNG using libpng.
Upon start ahsoka now seeks to the middle of the streams so that the
first image displayed is not frame 0, which is often just black.