Added a taskbar to the workspace thumbnail captions.

The caption taskbar displays the workspace app icons. App icons can be clicked to bring the desire app into focus or to minimize the app window.
Updated default stylesheet to include taskbar app icons
Separate GS34 stylesheet from GS36+ stylesheet and load appropriate one.
Rearranged workspace caption window apps (taskbar) position in Prefs dialog.
AppDisplay.AppIcon class no longer extends BaseIcon in GS38. Use IconGrid.BaseIcon class directly to create icons for workspace caption taskbar.
Updated installation zip for experimental taskbar
Separated workspace caption from background to accommodate resizing taskbar app icons.
Reworked taskbar container height so it doesn't resize when icons resized; Now using 16px for normal icons; Added class for focused app icon.
Only add gnome shell popup-menu-item class if shell version greater than 3.4
Added boxlayout container to center caption number, name, count, and spacer labels on x and y axis.
Reversed x_align of caption items so that extending items aligns them to the left; Fixed bug in _initWindowApps
Moved css styles to box layouts wrapping caption items - this fixed vertical centering issue.
Defined label boxes to prevent throwing errors; Fixed where windowcount images no longer transparent;
Added option for large app icons in taskbar; Adjusted css stylesheet for thicker (22px) caption.
Added binding for when caption app icon size changes
Added option to require mouse click to show dock over maximized windows.
Fixed GS36 bug introduced during GS38 port where dock fails to hide when entering overview apps or search mode.
Updated intellihide ungrab override and thumbnailsBox code for gnome shell 3.8.0.1 changes