Model Redesign: Added Reference Frames

Added Inverse Functions
UI Redesign
Cleaned Code

MathPad/MPToken.m

@@ -23,22 +23,22 @@
     return self;
 }
 
-- (instancetype)initWithRange:(NSRange)range inString:(NSString *)input
+- (instancetype)initWithRange:(NSRange)range stringValue:(NSString *)input
 {
     self = [super init];
     if (self) {
         _range = range;
-        _stringValue = [input substringWithRange:range].copy;
+        _stringValue = input.copy;
     }
     return self;
 }
 
 - (instancetype)initWithTokenType:(MPTokenType)tokenType
                             range:(NSRange)range
-                         inString:(NSString *)input
+                      stringValue:(NSString *)input
 {
     self = [self initWithRange:range
-                      inString:input];
+                   stringValue:input];
     if (self) {
         _tokenType = tokenType;
     }