move ParseErrorCode to error/error.h

In order to enable the customization of the error macros
 - RAPIDJSON_PARSE_ERROR_NORETURN
 - RAPIDJSON_PARSE_ERROR_EARLY_RETURN
the user may need to have access to the ParseErrorCode enum
already.  This requires a separate header location than the
GenericReader.

include/rapidjson/error/error.h

 #ifndef RAPIDJSON_ERROR_ERROR_H__
 #define RAPIDJSON_ERROR_ERROR_H__
 
-#include "../reader.h"	// ParseErrorCode
-
 ///////////////////////////////////////////////////////////////////////////////
 // RAPIDJSON_ERROR_CHARTYPE
 
@@ -29,6 +27,39 @@
 
 namespace rapidjson {
 
+///////////////////////////////////////////////////////////////////////////////
+// ParseErrorCode
+
+//! Error code of parsing.
+/*! \see GenericReader::Parse, GenericReader::GetParseErrorCode
+*/
+enum ParseErrorCode {
+	kParseErrorNone = 0,						//!< No error.
+
+	kParseErrorDocumentEmpty,					//!< The document is empty.
+	kParseErrorDocumentRootNotObjectOrArray,	//!< The document root must be either object or array.
+	kParseErrorDocumentRootNotSingular,			//!< The document root must not follow by other values.
+
+	kParseErrorValueInvalid,					//!< Invalid value.
+
+	kParseErrorObjectMissName,					//!< Missing a name for object member.
+	kParseErrorObjectMissColon,					//!< Missing a colon after a name of object member.
+	kParseErrorObjectMissCommaOrCurlyBracket,	//!< Missing a comma or '}' after an object member.
+
+	kParseErrorArrayMissCommaOrSquareBracket,	//!< Missing a comma or ']' after an array element.
+
+	kParseErrorStringUnicodeEscapeInvalidHex,	//!< Incorrect hex digit after \\u escape in string.
+	kParseErrorStringUnicodeSurrogateInvalid,	//!< The surrogate pair in string is invalid.
+	kParseErrorStringEscapeInvalid,				//!< Invalid escape character in string.
+	kParseErrorStringMissQuotationMark,			//!< Missing a closing quotation mark in string.
+	kParseErrorStringInvalidEncoding,			//!< Invalid encoidng in string.
+
+	kParseErrorNumberTooBig,					//!< Number too big to be stored in double.
+	kParseErrorNumberMissFraction,				//!< Miss fraction part in number.
+	kParseErrorNumberMissExponent				//!< Miss exponent in number.
+};
+
+
 //! Function pointer type of GetParseError().
 /*! This is the prototype for GetParseError_X(), where X is a locale.
 	User can dynamically change locale in runtime, e.g.:

include/rapidjson/reader.h

@@ -41,6 +41,8 @@ RAPIDJSON_DIAG_OFF(4127)  // conditional expression is constant
 	RAPIDJSON_MULTILINEMACRO_END
 #endif
 
+#include "error/error.h" // ParseErrorCode
+
 namespace rapidjson {
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -55,33 +57,6 @@ enum ParseFlag {
 	kParseValidateEncodingFlag = 2	//!< Validate encoding of JSON strings.
 };
 
-//! Error code of parsing.
-enum ParseErrorCode {
-	kParseErrorNone = 0,						//!< No error.
-	
-	kParseErrorDocumentEmpty,					//!< The document is empty.
-	kParseErrorDocumentRootNotObjectOrArray,	//!< The document root must be either object or array.
-	kParseErrorDocumentRootNotSingular,			//!< The document root must not follow by other values.
-	
-	kParseErrorValueInvalid,					//!< Invalid value.
-	
-	kParseErrorObjectMissName,					//!< Missing a name for object member.
-	kParseErrorObjectMissColon,					//!< Missing a colon after a name of object member.
-	kParseErrorObjectMissCommaOrCurlyBracket,	//!< Missing a comma or '}' after an object member.
-	
-	kParseErrorArrayMissCommaOrSquareBracket,	//!< Missing a comma or ']' after an array element.
-
-	kParseErrorStringUnicodeEscapeInvalidHex,	//!< Incorrect hex digit after \\u escape in string.
-	kParseErrorStringUnicodeSurrogateInvalid,	//!< The surrogate pair in string is invalid.
-	kParseErrorStringEscapeInvalid,				//!< Invalid escape character in string.
-	kParseErrorStringMissQuotationMark,			//!< Missing a closing quotation mark in string.
-	kParseErrorStringInvalidEncoding,			//!< Invalid encoidng in string.
-
-	kParseErrorNumberTooBig,					//!< Number too big to be stored in double.
-	kParseErrorNumberMissFraction,				//!< Miss fraction part in number.
-	kParseErrorNumberMissExponent				//!< Miss exponent in number.
-};
-
 ///////////////////////////////////////////////////////////////////////////////
 // Handler