pidgin/pidgin

Migrate gg, novel, null, sametime, silc, and zephyr to using G_DECLARE_FINAL_TYPE for their protocol objects

Testing Done:
Compile only.

Reviewed at https://reviews.imfreedom.org/r/620/
syntax: glob
.*.swp
.DS_Store
.flatpak-builder
*.pyc
*~
\#*\#
subprojects/*/
syntax: regexp
^build(.+)?\/
win32-install-dir(\.release)?
po\/pidgin\.pot$