BGE: New Property sensor evaluation types

This patch adds "Less Than" and "Greater Than" evaluation types to the property sensor.
The Wiki Docs modifications http://wiki.blender.org/index.php/User:Lordloki/Doc:2.6/Manual/Game_Engine/Logic/Sensors/Property
Also, I have attached a screenshot and a blend to check.

Reviewers: dfelinto, moguri

Reviewed By: moguri

Differential Revision: https://developer.blender.org/D476

source/gameengine/Expressions/StringValue.cpp

@@ -120,6 +120,13 @@ double CStringValue::GetNumber()
 
 
 
+int CStringValue::GetValueType()
+{
+	return VALUE_STRING_TYPE;
+}
+
+
+
 const STR_String & CStringValue::GetText()
 {
 	return m_strString;