Cloud merging: when sharing grammars between two devices that previously each
had separate grammar directoies on the server, clean up one of the directories
and make it a symbolic link to the other.
This lets the user access the same set of grammars from multiple devices.
Sharing grammars between multiple users is possible but discouraged at the
moment. There is no version handling, so concurrent editing of the same grammar
by different users might result in one user overwriting changes made by
another user. (The same goes for cuncurrent editing on multiple devices by
a single user, of course.)
Work in progress on making the online grammar editor use the new "gf -server"
mode instead of the old upload.cgi script. A first benefit is that the
editor now calls the server to check the syntax of lin & lincat definitions.
(But the links to minibar/gfshell/quiz are not available at the moment.)
When adding a new concrete syntax to a grammar, the currently open concrete
syntax will be copied. If the abstract syntax is currently open, the new
concrete syntax will start out empty.
