EXP-1824 FIX Received Items panel does not collapse correct when Height of panel is maximized in Inventory window

EXP-1829 FIX -- Selecting a valid item last allows other selected invalid items to be copied to Outbox with context menu option

* Updated context menu default enabled state to use the last state rather than
  TRUE.  Once per frame, the states are all reset to TRUE so this has the effect
  of AND'ing together successive buildContextMenu functions rather than ignoring
  previous states.

* Updated auto-open behavior to ignore items that are already open.

EXP-1827 FIX -- Drag area in outbox does not always highlight green when indicating a top level drop

* Updated the outbox drop area highlight to include top level drops within the
  outbox inventory panel itself.

* Updated to latest text per Leo's comment in the JIRA.

EXP-1550 FIX -- New tag shown and not removed on click when rezzing an item from Received Items panel and taking back into inventory.

* Inventory folder creation dates are now only set once, rather than being
  updated every time a new item is added.

* Added handleHover function to clear highlight

EXP-1125 FIX -- New tags always shown in Received Items inbox when Inventory window is detached from side panel
EXP-1578 FIX -- received items folder shows shadows of content when scrolling through lots of folders in same window

* Put in guard to prevent the inventory panel from being created multiple times

made minimum size reflect default size for 1024 width window of old layout stack
no way to match behavior

EXP-1791 FIX -- Handle case where initialization with SLM fails in the Merchant Outbox floater in the viewer

* Timeout now triggers the re-initialization logic in the merchant outbox.

* Added support for marketplace notifications that don't display the dialog
  until the next frame, leaving room for the drag and drop operation to
  properly complete before the notification shows up and interferes.

EXP-1810 PROGRESS -- Cannot resize Received items panel in Inventory window

* Updated "copy to merchant outbox" context menu and drag and drop code to block calling cards.
* Changed user_resize to true on the "Received Items" panel and the main inventory panel

* Updated context menu code to enable visible items that aren't explicitly disabled.

EXP-1758 : Fix crash on login on Mac (bad pointer reference). Might need more work if the intent was to always get that pointer.

The whole sentence was split to two parts:
 First pars was in panel.string and the second one in the text box. I combined them both in "allow_label5" text box and also I deleted unnecessary panel.string with the first part of the sentence.

EXP-1758 WIP Progress spinner not shown during merketplace synch if Merchant Outbox floater was previously minimized
rewrote layout_stack resizing logic to be symmetrical