get rid of clang compile warnings

- type conversions (type casts) and no return on non-void function
Merge remote-tracking branch 'upstream/master'

* upstream/master:
  Implement option to set a capture limit
  Fix payload memory free when detroying messages
  Fixed Color indicator in Call Flow window title
  Call list can be cleared by pressing F5
Merge pull request #10 from miconda/master

get rid of clang compile warnings