Update plagin compatible with glib 2.32 (threading) and glib 2.36 (g_type_init was depricated)
Fix sound volume control from mpris client to mpris player

Bump version in autotools. Update configure.ac for the new version
of autoconf (1.14)
Merge pull request #13 from sakal/master

Fix errors on compile and fix volume value while control from mpris client