First drop of the completely rewritten dialogue module
Document dialogue conversation/reply message state constants
Updated action buttons CSS classes and automplete placeholder
Added new trashed state and removed redundant cache method get_user_brief_details
Created a separate render method for reply class, reverted lang_string calls to get string and some documentation.
Tidy up of code in conversation page
Changed get_string for trashing a conversation
Tidy up of code in reply page
Added redirect to drafts page for save and trash submission actions
Fixed check on conversation page to see if still open and can display reply form
Added a session cache to remember application state for user experience
Added function to cache params for course module instance, used in display controls to remember state for user experience
Various strings added
Removed method conversation_list_buttons as use other methods to render state and show button groups
Replaced new lang_string calls with get_string calls and added cached param support for state and show params
Moved the get conversation participants code out of dialogue class into own function, quick fix to conversation listing code when using group selector
Changed the get participants cache call to dialogue_get_conversation_participants
Changed the get participants cache call to dialogue_get_conversation_participants
Added unread_counts function to replace get_unread_count function
Replaced unread count call with new unread counts call