Gk browser find realm files

Displays all realms on the hard drive in a convenient menu

https://www.dropbox.com/s/tvbckphmqag28nk/Screenshot%202014-09-08%2016.35.13.png?dl=0

Please be explicit in property semantics:
```objc
@property (nonatomic, weak) IBOutlet NSMenu *fileMenu;
@property (nonatomic, weak) IBOutlet NSMenuItem *openMenuItem;
@property (nonatomic, weak) IBOutlet NSMenu *openAnyRealmMenu;

@property (nonatomic, strong) NSDateFormatter *dateFormatter;

@property (nonatomic, assign) BOOL didLoadFile;
@property (nonatomic, strong) NSMetadataQuery *query;
@property (nonatomic, strong) NSArray *groupedFileItems;
```