IDProperty python module update

- add support for IDProp array slicing, but not resizing.
- rename array attribute type to typecode and use chars 'f', 'd', 'i' which match pythons array module. (was using int's which only have a meaning internally).
- rename function 'convert_to_pyobject' to 'to_dict' and 'to_list' for IDProp group and array types respectively.
- remove 'len' array attribute, calling len(array) is fine.

source/blender/python/generic/py_capi_utils.h

@@ -35,7 +35,7 @@ void			PyC_LineSpit(void);
 PyObject *		PyC_ExceptionBuffer(void);
 PyObject *		PyC_Object_GetAttrStringArgs(PyObject *o, Py_ssize_t n, ...);
 void			PyC_FileAndNum(const char **filename, int *lineno);
-int				PyC_AsArray(void *array, PyObject *value, int length, PyTypeObject *type, const char *error_prefix);
+int				PyC_AsArray(void *array, PyObject *value, const int length, const PyTypeObject *type, const short is_double, const char *error_prefix);
 
 /* follow http://www.python.org/dev/peps/pep-0383/ */
 PyObject *		PyC_UnicodeFromByte(const char *str);