FIX warnings (static method and Undefined indexes)
FIX typo of separated
FIX further warnings and static usage notices
FIX further islet warnings
FIX typo in email
FIX further warning on resend of email
FIX another warning isset()
FIX typo in invite_action
CHANGE message shown to user to be more grammatically correct
FIX static $rewrite_on removed as it's called non-statically
FIX Adding multiple people at once now generates different hashes for each person
FIX additional isset check for warnings when multiple delete invites
FIX add user to blog when $accepted *is* empty
FIX typo on invitations button