Fixed #1786: Add support to specify video format when opening video preview



git-svn-id: http://svn.pjsip.org/repos/pjproject@4921 74dad513-b988-da41-8d7b-12977e46ad98
Fixed #1787: Failure of DShow device to open a certain resolution



git-svn-id: http://svn.pjsip.org/repos/pjproject@4922 74dad513-b988-da41-8d7b-12977e46ad98
Fixed #1783: Restart ICE if a mid-dialog re-INVITE contains no offer



git-svn-id: http://svn.pjsip.org/repos/pjproject@4923 74dad513-b988-da41-8d7b-12977e46ad98