use long long rather then int for storing game logic properties.

There were also some problems with int to python conversion
- assigning a PyLong to a KX_GameObject from python would raise an error
- PyLong were coerced into floats when used with internal CValue arithmetic

Changes...
- PyLong is converted into CIntValue for coercing and assigning from python
- CValue's generic GetNumber() function returns a double rather then a float.
- Print an error when a PyType cant be coerced into a CValue

Tested with python, expressions and property sensor.

source/gameengine/Expressions/StringValue.cpp

@@ -113,7 +113,7 @@ this object
 
 
 
-float CStringValue::GetNumber()
+double CStringValue::GetNumber()
 {
 	return -1;
 }