Decreased size of MySQL table key.
Removed mod_mam_cache module (replaced by mod_mam_cache_user).
Moved SQL code from mod_mam_odbc_async_writer to mod_mam_odbc_arch.
Moved SQL code from mod_mam_muc_odbc_async_writer to mod_mam_muc_odbc_arch.
Fixed removing users from ejabberd_users.
Moved SQL code from mod_mam_muc_odbc_async_writer to mod_mam_muc_odbc_arch.