Added Function Chooser as a Popover

Improved Evaluation
Added Parenthesis Function

MathPad/MPFunctionsViewController.h

@@ -0,0 +1,24 @@
+//
+//  MPFunctionsViewController.h
+//  MathPad
+//
+//  Created by Kim Wittenburg on 28.09.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import <Cocoa/Cocoa.h>
+
+@class MPFunctionsCollectionView;
+
+@interface MPFunctionsViewController : NSViewController
+
+- (id)init;
+
+@property (weak) IBOutlet MPFunctionsCollectionView *collectionView;
+@property (nonatomic, strong) NSArray *functionPrototypes;
+@property (nonatomic, strong) NSString *currentDescription;
+
+@property (nonatomic, weak) id target;
+@property (nonatomic) SEL action; // 1 argument: The function to insert
+
+@end