Analysis Types for Pie Chart! (v2)

Addresses Issues #1799 and #1805 

Made some modifications to my last patch per request from @jaypoulz 

**Change Summary:**
1.  Analysis Types for Pie Charts reworked for compatibility with Default Vises
2.  Analysis Types no longer break Pie Chart Tooltips
3.  Pie Chart Tooltips are redone to model the Bar Chart Tooltips, displaying the value of the grouping field, the analysis type, and the value of the field being displayed
4.  Modified the Base Vis drawToolControls method to display "No <Name of Grouping Field with Null Value> if the field is null.  Ex:  If grouping by a text field entitled "Label", a data point with a null value for the Label field will display "No Label."  The presence of text prevents styling from breaking.
5.  Bar Chart and Pie Chart Tooltips now also display (4) for visual consistency and clarity.

why does @displayData need to be global? It is used somewhere else in the file?