Model Redesign: Added Reference Frames

Added Inverse Functions
UI Redesign
Cleaned Code

MathPad/MPParenthesisFunctionLayout.m

@@ -128,16 +128,6 @@
     return [NSIndexPath indexPathWithIndex:0];
 }
 
-- (NSUInteger)indexOfLeadingChild
-{
-    return 0;
-}
-
-- (NSUInteger)indexOfTrailingChild
-{
-    return 0;
-}
-
 - (NSIndexSet *)indexesOfRemainingChildren
 {
     return [NSIndexSet indexSetWithIndex:0];