Fix project warnings

Author: lobianco

Source/MMScanner.m

@@ -45,7 +45,7 @@
         default:
             [NSException raise:@"Invalid delimiter character"
                         format:@"Character '%C' is not a valid delimiter", character];
-            return '\0';
+            return nil;
     }
 }
 
@@ -322,6 +322,10 @@ - (NSUInteger)skipIndentationUpTo:(NSUInteger)maxSpacesToSkip
 - (NSUInteger)skipNestedBracketsWithDelimiter:(unichar)delimiter
 {
     NSString *delimiters     = __delimitersForCharacter(delimiter);
+
+    if (delimiters == nil)
+        return 0;
+
     unichar   openDelimiter  = [delimiters characterAtIndex:0];
     unichar   closeDelimeter = [delimiters characterAtIndex:1];
 

Source/MMSpanParser.m

@@ -108,7 +108,7 @@ - (NSArray *)parseSpansInTableColumns:(NSArray *)columns withScanner:(MMScanner
 
 #pragma mark - Private Methods
 
-- (NSArray *)_parseWithScanner:(MMScanner *)scanner untilTestPasses:(BOOL (^)())test
+- (NSArray *)_parseWithScanner:(MMScanner *)scanner untilTestPasses:(BOOL (^)(void))test
 {
     NSMutableArray *result = [NSMutableArray array];