Fixed char server's maintenance mode

Enabling the maintenance mode will now restrict login based on group id (previously maintenance mode was merely cosmetic and would allow all accounts to access).
Renamed char-server.conf setting char_maintenance to char_server_type, added char_maintenance_min_group_id to be used in conjunction with char_server_type:1

Signed-off-by: shennetsind <ind@henn.et>
Updated char server's response to offline map server

Previously attempting to log in while map server was unavailable or not yet ready would close the client, now the char select window shows up and attempting to select a character while the map server is unavailable will display a pop up "the map is not available", client will remain in char select window and won't close anymore.
Special Thanks to Haruna.

Signed-off-by: shennetsind <ind@henn.et>
Fixed atcommand alias bug on selected commands

Modified the issues in question to check against the source command name, ensuring that the conditions work even when an alias is used. Also replaced sensitive conditions with insensitive ones, Special Thanks to Haruna.

Signed-off-by: shennetsind <ind@henn.et>
Minor char server char list fixes

the array was being erroneously modified in old client packets.

Signed-off-by: shennetsind <ind@henn.et>
Fixed a mapserver crash when using SQL item DB and an item's script is NULL

- Special thanks to Mumbles.

Signed-off-by: Haru <haru@dotalux.com>
Introducing Character Ban Support.

@charban/@charunban, can temporarily block any accounts as opposed to the usual account-wide block.
Special Thanks to Haruna, Yommy!

Signed-off-by: shennetsind <ind@henn.et>
Merge branch 'master' of https://github.com/HerculesWS/Hercules
Renewal elemental attr fix

I'm committing on malufett's behalf.

Signed-off-by: shennetsind <ind@henn.et>
Update rAthena-main-upgrade.sql

Follow-up aee2f6317e1c927847993801b5973d7e2e27a418
Added emblem blank pixels check

- Made possible thanks to (and using base code by) Ai4rei - eAthena
  r15263 and add-on patch
  http://hercules.ws/board/topic/2974-add-on-patch-for-ea-r15263-commit/
- Modified to allow checking for a percentage of transparent pixels
  rather than full image transparency.
- Tweaked to accept some other bmp formats that are currently allowed
  by the client.
- The performance hit from enabling this check is negligible (benchmarks
  show that scanning an emblem requires about half the time required to
  decompress it after it's received), but it does exist, as noted in the
  configuration file.
- Special thanks to Ind.

Signed-off-by: Haru <haru@dotalux.com>