Merge pull request #6 from knocte/master

Several versioning and gitignore polish
metadata: Added fixup for GstTag
Object: Fixed compilation on .NET

Using variables cannot be modified in .NET but can be in mono
so switch to a good old Dispose call here.

https://bugzilla.xamarin.com/show_bug.cgi?id=15832#c0
metadata: Move gstreamer lib renaming to the right part
.gitignore: ignore more stuff
build: fix glue includes in distros with older gstreamers