Adds scale to fill content view

+ Adds feature which resizes columns with weighted distribution across entire width of data table frame if the content is smaller
+ Creates new delegate method allowing the user to decide if they want the content view to automatically scale to fill to the data table frame width

+ Refactors the way content width is calculated
+ Fixes bug where Data Grid would crash if the content width was smaller than the width of the frame
+ Trims row columns to the header count specified