* on paste, ask if unknown branches shall be added to the branch list
(entails new LFUN_BRANCH_ADD)
* add a list of undefined branches to the buffer and the GUI
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@30419 a592a061-630c-0410-9148-cb99ea01b6c8