added serialisation/transmission of video data

git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@7452 b45a01b8-16f6-495d-af2f-9b41ad6348cc
bug fix in video sending

git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@7453 b45a01b8-16f6-495d-af2f-9b41ad6348cc