Remove the size argument from IsChannel and IsNick.

There was only one case (which was probably an error) where these
methods were not set to their ServerLimits value.
Merge pull request #543 from SaberUK/master+sizeparam-removal

Remove the size argument from IsChannel and IsNick.
Deduplicate hex string creation code
irc::stringjoiner cleanup

- Get rid of unused constructors
- signed -> unsigned
- return const ref from GetJoined()
irc::tokenstream and irc::sepstream cleanup

irc::sepstream does not require virtual methods
Remove unused UserManager::ServerPrivmsgAll()
Get rid of the NICKForced extension

Don't run OnUserPreNick when the nick change is forced
Change the signature of User::ForceNickChange() to accept const std::string& instead of const char*
Added macro to allow simpler logic in functions with the need to vsnprintf
Replaced vsnprintf with VAFORMAT pretty much everywhere.
Merge pull request #542 from ShutterQuick/inspircd+printfcleanup

Replaced all the individual vsnprintfing with a macro
Fixup last commit
Remove OnUserPreNotice and OnUserNotice hooks, add MessageType argument to OnUserMessage and OnUserPreMessage

All modules (except m_nonotice) that perform filtering on messages have common logic for handling PRIVMSGs and NOTICEs and most of them run the exact same code in both cases