basic packet splitting for video frames
used define instead of constant.. removed unecessary value from packet
unrelated: got rid of some warnings
dont rely on undefined behaviour
Merge branch 'notsecure-split-video'
only allow call cancel during a pending invite
Merge branch 'JFreegman-avcancel'
Fixed video bitrate being set way higher than it should.

Video bitrate is set in kb/s not b/s.
Some video tweaks.
Tweaked conjestion control algorithm.

File transfers should now work better.
Fixed some more possible issues with file transfers/conjestion control.
Lowered video bitrate to 500kb/s and lowered audio buffer size.
Fixed segfault that happened because calls could be hanged up more
than once.
Fixed possible bug if more than one ringing msi packet was sent to us.
Fixed calling msi_reject more than once possibly causing issues.
remove pointer type warnings when building with mingw