CHUI-847 Fixed [CHUIBUG]Collapse Participant List, operates on all torn off chats: make flag mIsPartListExpanded for saving of the participant list panel expand/collapse state

CHUI-831 Minimized conversation floater is not opened with Open Conversation Window preference if conversation receiving message is selected : force unminimized of the session's floater

CHUI-793 : Fixed! Introduced ChatLoadGroupTimeout and ChatLoadGroupMaxMembers to mitigate slow group loading.

CHUI-809 FIXED Changes in menu items to make them consistent. Do not start IM if selected person is self.

CHUI-840 (Right clicking on unselected group conversation can have unpredictable results for menu options)

CHUI-793 : WIP : Limit the number of participants we load on groups when we load from the local group data

CHUI-821 ADD FIX Conversation size regression when logging out with conversation list minimized to icons:
deleted redundant savings of the convers. panel width;
added a manually reshape of the conv. panel after change it's collapse state;
function with uninformative name "updateState" was renamed to "reshapeFloaterAndSetResizeLimits"

CHUI-738 FIXED Your own nametag disappears - mysteriously: reset display time when nametag is changes

CHUI-835 (ctrl-h does not select nearby chat conversation in list): Modified setVisibleAndFrontMost() to now take a arguement for the key that was pressed (if one was pressed). This allows the floater to select the converation line item when becoming visible/frontmost.

CHUI-772 FIX User sees no notification of conversation activity not visible in long scrolling conversation list
Added call to mConversationsRoot->arrange() in LLFloaterIMContainer::isScrolledOutOfSight()

CHUI-832 (Different conversation than is selected shown in message panel after tearing off conversation): Now when a conversation is torn off an adjacent conversation is selected (but not focused).

CHUI-823 ([CHUIBUG]Triple-clicking on the scroll back button in the CHUI causes all the conversation to be selected)

CHUI-834 (Conversation selection in conversation list does not update when redocking torn off conversations): Now when click to dock a torn off floater, the correct conversation line item will be selected.