MongooseIM 1.3.0

• added XEP-0313: Message Archive Management support (mod_mam)
• ported LDAP authentication from ejabberd
• added PostgreSQL support
• disabled SSL 2.0 support
• disabled old unsafe ciphers
• made the repo includable as a rebar dependency
• made the whole codebase use #xmlel{} instead of {xmlel, ...}