Removed get_state call from mod_muc_log. Added mod_muc_room:get_users/1. Improved code readability.  It is partically backported 0bd9b45f with fixes from 4f7320ac.

Renamed functions list_to_* to binary_to*.
Added getters for #state.access.
New helpers foreach_matched_jid, foreach_matched_user, erase_matched_users.
Replaced SRole with BRole.
Added mod_muc:room_jid_to_pid/1.
mod_muc_log do not know nothing about the internal representation of a mod_muc_room process.
Renamed mod_muc_room:get_users/1 to mod_muc_room:get_room_users/1. Added mod_muc_room:is_room_owner/2. This is partically backported ec58bb6c37 from arc-mod-mam.
Cleaning MUC code: introduced better variables' names. It is backported 1ab152c8.
Fixed a bug (access to a wrong variable) in MUC. It is backported 4f5f1a24.
Split mod_muc_room:destroy_room/2 into a set of functions. It is backported be482b3e4a2.
Split mod_muc_room:process_presence/4. It is backported d5825e9bab.
Split mod_muc_room:add_new_user/4. It is backported b38d6c2d.
Prettified mod_muc_room:set_opts/2. It is backported 429c90203b.
Rewrote get_mucroom_disco_items. It is backported f66c63df.
Split mod_muc_room:check_invitation/4. It is backported a936c7d02.
Rewrote check_voice_approval. Replaced catch with try catch:throw -> ... end.
Fixed indention.
Merge pull request #104 from arcusfelis/arc-pretty-muc

Prettify mod_muc