`glib-genmarshal` and `glib-mkenums` use a `Color` class which
implements a number of print_* methods to print colored messages
to the standard error output.
In order to be consistent with those programs' output,
`gdbus-codegen` has also started using that same class and methods.
https://bugzilla.gnome.org/show_bug.cgi?id=791015
Previously, this would not work, as it would result in comparing the
order of a string and an integer. Make it work, and make 'UNRELEASED'
compare higher than other versions so it's always treated as the latest
version.
'UNRELEASED' is commonly used by maintainers to highlight new API while
it's being prototyped, until they know which version it will actually
be released in. At the time of release, they replace all 'UNRELEASED'
strings in git with the new version number.
An example of this usage is here:
d380ac6a2a (9208ee267cb05db1afd3a5c323d71e51db489447_7619_7656)https://bugzilla.gnome.org/show_bug.cgi?id=769995
Most changes were just replacing usage of "has_key" with "in".
Also updated the sorting function which was simplified and
changed to a "key" function instead of "cmp" (which is no longer
supported in python3. Verified everything builds with
python 2.7 and 3.
https://bugzilla.gnome.org/show_bug.cgi?id=678066
