fixed not serializing named values when values provided from code

Reviewed by Richard.

added ability to specify clip rects in textures.xml

added Flag as value type
moved Batch to BatchBlock
renamed Choice to ChoiceBlock
made merging of parameters for ValueParams consistent (fillFrom and overwriteFrom are inverses of each other now)
made iteration over Multiple<T> type params easier
initial schema param blocks

initialized with chrome.

  is still problematic for FUI floaters.

EXP-1205 PROGRESS -- As a User, I want a toybox which will contain all buttons that I can d&d into the toolbars
EXP-1268 FIX -- The "Restore Defaults" button should reset the left/right/bottom toolbars to their default states

* LLToolBarView::loadDefaultToolbars now a static function
* Toybox button callback hooked up to properly restore defaults

Reviewed by Merov

EXP-1264 Chat log shows as blank if closing viewer with chat log open and then opening chat floater on next login
EXP-1271 Remove UI hints

 * Hooked up commands to their respective floaters

  on the localized button labels.

EXP-1211, EXP-1257 : Save and load the button type along with the toolbars, add a force default load option, enforce consistency between menus and toolbars

Toolbar buttons now affect their floaters as indicated in the FUI_Button_states
wiki page -- https://wiki.lindenlab.com/wiki/FUI_Button_states

- Removed all sidetray dependencies and the sidetray itself.

- Also removed LLFloaterSidetrayTab and LLSidetrayListener as unused.

EXP-1205 PROGRESS -- As a User, I want a toybox which will contain all buttons that I can d&d into the toolbars
EXP-1233 FIX -- Populate the toybox floater window with all FUI toolbar buttons indicated as such in the "commands.xml" definition.
EXP-1267 FIX -- Enable/disable buttons in the toybox

* Hooked up button callbacks to the toolbar buttons
* Fixed toybox button enable/disable to function properly and live update as
  buttons change states.
* Removed the toybox toolbar background image

Reviewed by Leyla

EXP-1257 : Implemented loading of toolbar settings per user account. Also factorize a bit and clean up the related saveToolbars code.

EXP-1262 Hitting single letters reserved for shortcuts inworld opens chat but not associated shortcuts (like Mouselook and Fly)
EXP-1266 Communicate > Nearby Chat menu item does not bring up chat floater