Allow multiple allowmasks in link blocks, #679
Fix a few issues

- Rehash notices
- Modes in CAPAB
- GetTargetAndAction() not being static in m_callerid
- Loading custom configuration files using --config. (@SaberUK)
- ServerConfig::Read not using std::endl. (@SaberUK)
- Out of date comments in opers.conf.example, issue #624