Autogenerating the ChangeLog for *mm modules.

[José Alburquerque <jaalburquerque gmail com>]

Hi.  I pushed some changes to the *mm modules in git that use mm-common
and don't already automatically generate their ChangeLog from the git
commit messages so that the ChangeLog is automatically generated form
the git commit messages when doing a 'make dist'.  I did it so that when
changes are committed, if the changes are in the commit message but not
in the ChangeLog, the ChangeLog in the tarball is still accurate.

I recall some time ago that it was discussed that it would be nice to
remove the need to commit changes to the ChangeLog because it is at
times cumbersome.  I also noticed some recent commits in glibmm that
prompted me to commit without the ChangeLog as well, both in glibmm and
in the gtkmm-documentation module.  To ensure that these changes appear
in the ChangeLog of released tarballs and are not lost, I made the
changes in glibmm and gtkmm-documentation.  After, for convenience I
added the changes to the rest of modules so that if anyone just includes
the changes in the commit message and not in the ChangeLog, the
ChangeLog is still accurate when releasing.

This does not mean that modifying the ChangeLog is a problem.  It only
ensures that changes that are committed without modifying the ChangeLog
(but including the entry in the git commit message) are still reflected
in the ChangeLog of a released tarball.  I hope this is okay.

These are the modules that were modified:
clutter-box2dmm
clutter-gtkmm
cluttermm
gconfmm
glibmm
goocanvasmm
gtkmm
gtkmm-documentation
libgdamm
libgda-uimm
libsigc++2
libxml++
pangomm

-- 
José