Replace some C-isms with C++-isms.

* 'const char*' to 'const std::string&'.
* snprintf to std::string concatenation.
* Replace duplicated OneOfMatches with InspIRCd::MatchMask.
Merge pull request #531 from SaberUK/master+snprintf-removal

Replace some C-isms with C++-isms.
Tidy up keywords on module methods.

- Remove virtual keyword from a ton of methods which don't need it.
- Add override keyword to a ton of methods which do need it.
Merge pull request #514 from SaberUK/master+virtual-cleanup

Remove virtual keyword from a ton of methods which don't need it, introduce CXX11_OVERRIDE.
Allow spaces (and more) in oper types

The spaces are converted to '_' characters in OPERTYPE for 2.0 servers
Issue #533 suggested by @ankitkv
irc::Spacify--
m_joinflood Make the code friendlier, unset +j when the module is unloaded

See 21c3232b8e0bb41727f2d65a0b2d5304587cf6be and fae560cddc389b88c9cd34afdccf9035f4d11c5b
Get rid of strlcpy(), strlcat(), charlcat() and charremove()