Add Complete Support for Live Inferencing

[Pranjal2041]

Enable live Inferencing from webcam. For fast performance program stores result of mpt and hmr of last few frames and combines them with that of latest frame and feeds them to encoder and regressor. Achieves speed of approximately 12fps(for sequence_length=16) on my gtx1060. Only caveat is rendering results can't be displayed in real time and only single person can be tracked at a time. Arguments:-

1. live_display :- Show bbox around person in realtime.(Slows inferencing by a small amount)
2. max_frames :- Max number of recorded frames after which recording will automatically stop(Can be stopped in middle by pressing 'q')
3. sequence_length :- Number of frames to be fed to encoder. #115 #40

[mkocabas]

Hi @Pranjal2041,

This looks awesome. I plan to test it over the weekend, if everything works fine I will merge it. Thanks for your time and effort!

[magrenimish]

Hi @mkocabas were you able to test these changes for webcam demo? If yes, what speed did you approximately achieve? Thanks