Added quoted scalars (with escaping).

Refactored some common whitespace-parsing code in scanning both scalars.
Implemented the flow collection tokens.

exceptions.h

@@ -12,4 +12,21 @@ namespace YAML
 	class IllegalMapValue: public Exception {};
 	class IllegalScalar: public Exception {};
 	class IllegalTabInScalar: public Exception {};
+	class DocIndicatorInQuote: public Exception {};
+	class EOFInQuote: public Exception {};
+	class UnknownEscapeSequence: public Exception {
+	public:
+		UnknownEscapeSequence(char ch_): ch(ch_) {}
+		char ch;
+	};
+	class NonHexNumber: public Exception {
+	public:
+		NonHexNumber(char ch_): ch(ch_) {}
+		char ch;
+	};
+	class InvalidUnicode: public Exception {
+	public:
+		InvalidUnicode(unsigned value_): value(value_) {}
+		unsigned value;
+	};
 }