Changes

1. One more flow of internal changes and flexibility enhancements. Basically while building commercial plugins I'm extending core with more templates overrides and events listeners options
2. Three new attributes in departments which can be used in extensions.
3. Few fixes regarding user arguments variables. It was lost during form submitting. It was effecting only extensions.
4. Custom forms field can be managed from back office. Basically admin can add custom fields directly from back office. No need to use Javascript. This option can be found in start chat form settings page.

For update just follow standard update procedure For manual update it's update_106.sql