fixed JSON testsuite errors and warnings with VS2012

JSON/src/Query.cpp

@@ -101,11 +101,11 @@ Var Query::find(const std::string& path) const
 			{
 				if ( firstOffset == -1 )
 				{
-					firstOffset = matches[0].offset;
+					firstOffset = static_cast<int>(matches[0].offset);
 				}
 				std::string num = token->substr(matches[1].offset, matches[1].length);
 				indexes.push_back(NumberParser::parse(num));
-				offset = matches[0].offset + matches[0].length;
+				offset = static_cast<int>(matches[0].offset + matches[0].length);
 			}
 
 			std::string name(*token);

JSON/testsuite/src/JSONTest.cpp

@@ -214,7 +214,7 @@ void JSONTest::testStringProperty()
 	Object::Ptr object = result.extract<Object::Ptr>();
 	Var test = object->get("test");
 	assert(test.isString());
-	std::string value = test;
+	std::string value = test.convert<std::string>();
 	assert(value.compare("value") == 0);
 }
 
@@ -360,7 +360,7 @@ void JSONTest::testObjectProperty()
 
 	test = object->get("property");
 	assert(test.isString());
-	std::string value = test;
+	std::string value = test.convert<std::string>();
 	assert(value.compare("value") == 0);
 }
 
@@ -556,7 +556,7 @@ void JSONTest::testStringElement()
 	Array::Ptr array = result.extract<Array::Ptr>();
 	Var test = array->get(0);
 	assert(test.isString());
-	std::string value = test;
+	std::string value = test.convert<std::string>();
 	assert(value.compare("value") == 0);
 }