Added Lots of Documentation

Added some nice to haves
Improved and Unified General Code Layout

MathKit/MPSumTerm.m

@@ -8,10 +8,7 @@
 
 #import "MPSumTerm.h"
 
-#import "MPParsedExpression.h"
-#import "MPProductTerm.h"
 
-#import "MPToken.h"
 
 @implementation MPSumTerm
 
@@ -26,6 +23,7 @@
     return self;
 }
 
+
 - (NSDecimalNumber *)doEvaluation:(NSError *__autoreleasing *)error
 {
     NSDecimalNumber *value = [NSDecimalNumber zero];