allow for generic bundle resource retrieval

@@ -167,6 +167,7 @@ typedef enum : NSUInteger {
 - (void)setFrame:(CGRect)frame;
 
 + (UIImage *)resourceImageNamed:(NSString *)imageName;
++ (NSString *)pathForBundleResourceNamed:(NSString *)name ofType:(NSString *)extension;
 
 #pragma mark - Movement
 

@@ -405,16 +405,20 @@
 
 + (UIImage *)resourceImageNamed:(NSString *)imageName
 {
-    NSAssert([[NSBundle mainBundle] pathForResource:@"MapBox" ofType:@"bundle"], @"Resource bundle not found in application.");
-
     if ( ! [[imageName pathExtension] length])
         imageName = [imageName stringByAppendingString:@".png"];
 
-    NSString *bundlePath = [[NSBundle mainBundle] pathForResource:@"MapBox" ofType:@"bundle"];
+    return [UIImage imageWithContentsOfFile:[[self class] pathForBundleResourceNamed:imageName ofType:nil]];
+}
+
++ (NSString *)pathForBundleResourceNamed:(NSString *)name ofType:(NSString *)extension
+{
+    NSAssert([[NSBundle mainBundle] pathForResource:@"MapBox" ofType:@"bundle"], @"Resource bundle not found in application.");
+
+    NSString *bundlePath      = [[NSBundle mainBundle] pathForResource:@"MapBox" ofType:@"bundle"];
     NSBundle *resourcesBundle = [NSBundle bundleWithPath:bundlePath];
-    NSString *imagePath = [resourcesBundle pathForResource:imageName ofType:nil];
 
-    return [UIImage imageWithContentsOfFile:imagePath];
+    return [resourcesBundle pathForResource:name ofType:extension];
 }
 
 - (void)dealloc