Many deprecated functions in gtk+, gtkmm does not build with --enable-warnings=fatal

[Kjell Ahlstedt <kjell ahlstedt bredband net>]

If you don't build gtkmm from the latest sources in the git repository, 
you can stop reading here.

During the last few days many functions and some whole classes have been 
deprecated in gtk+, causing gtkmm builds to fail if --enable-warnings=fatal.
I'm working on fixing this (by deprecating a lot of stuff in gtkmm), but 
it will take some time. It feels like I'm shooting at a moving target 
right now. There are more deprecations in gtk+ almost each day. The 
deprecations are not yet consistent. There are still several 
non-deprecated gtk+ functions that take a parameter of a deprecated class.

Just wanted to inform that I'm working on it.
If anyone else is also working on it, please tell me. Then one of us can 
stop the work and wait for the other one to finish.

Kjell