protocol: Add is_extban() to allow modules to check if the ircd considers a mask an extban
chanserv/quiet: Don't try to expand extbans
chanserv/ban: Don't try to expand extbans
Add UF_SERVICE user flag and some support in proto modules
Add UF_SERVICE to internal clients
chanserv/sync: Skip sync on external services clients (closes #363)
Add external services NEWS item
protocol/inspircd: Add umode +k as UF_IMMUNE
Merge pull request #370 from aji/external-services

chanserv/sync: Skip sync on external services clients (closes #363)
libathemecore: add RFC1459 username character attributes (ref #301)
libathemecore: add is_valid_username(). (ref #301)
botserv/main: use is_valid_username() and trim usernames to USERLEN (closes #301)
botserv/main: do not load invalid usernames from database
operserv/clones: do not pass a potentially undefined value to timediff().  (closes #206)
groupserv: move groupacs membership accounting to exist under myentity_t. (ref #302)
groupserv: myuser_group_count_flag now works with all entities
groupserv: store myentity_t in access entries.
groupserv: make groupserv core entity-agnostic (ref #302)
groupserv/{flags,fflags}: allow adding any kind of entity to a group
groupserv: allow group inheritance to work for a single level (using a recursion guard).