pidgin/pidgin

Port PurpleBlist to use PurpleAccountManager::added and ::removed signals and remove the old purple signals

Testing Done:
Connected a Bonjour and Demo account without issue.

Reviewed at https://reviews.imfreedom.org/r/2034/
REVIEWBOARD_URL = "https://reviews.imfreedom.org/"
REPOSITORY = "pidgin/pidgin"
REPOSITORY_TYPE = "mercurial"
BRANCH = "default"
LAND_DEST_BRANCH = "default"
LAND_PUSH = False