videorepair: Don't restrict caps to nal-aligned h264

In general videorepair could work for ANY caps, but that's for later.
For now let's just have it handle any kind of h264 to work properly
with different decoders.
videorepair: Set proxy caps flag on sink and src pads

The element itself doesn't worry about the caps, so we can avoid some
standard caps handling code.
videorepair: Register callback function names for debug
videorepair: Reset element state on PAUSED->READY