Expose tokenizer's position variables for better error reporting

HTMLKit/CSSTokenizer.h

@@ -36,6 +36,9 @@ typedef NS_ENUM(int, CSSToken)
 
 @interface CSSTokenizer : NSObject
 
+@property (nonatomic, readonly) size_t currentPosition;
+@property (nonatomic, readonly) size_t tokenPosition;
+
 - (instancetype)initWithString:(NSString *)string;
 
 - (CSSToken)nextToken;

HTMLKit/CSSTokenizer.m

@@ -19,6 +19,8 @@
 @end
 
 @implementation CSSTokenizer
+@synthesize currentPosition = _currentPosition;
+@synthesize tokenPosition = _tokenPosition;
 
 - (instancetype)initWithString:(NSString *)string
 {