pidgin-guifications-2.16-bp156.3.5

- Rename pidgin-guifications-lang to pidgin-plugins-guifications-lang.
- Reference a tarball source URL.
- Rename 'sr@Latn' to 'sr@latin', 'no' to 'nb_NO' only on SLE 11.
- Remove messenger examples from the description.
- Spec cleanup.

- Create a pidgin-plugin-guifications subpackage, for consistency
  with other pidgin plugins.
- Replace License tag with spdx identifier (GPL-2.0+).

- Clean package for Contrib.