Python Panels WIP

- Register python panels
- Added a generic class checking function BPY_class_validate() for panels/operators.
- No button drawing yet

Brecht, Added RNA_enum_value_from_id() and RNA_enum_id_from_value() to rna_access.c to do lookups between identifiers and values of EnumPropertyItem's, Not sure if these should go here.

source/blender/python/intern/bpy_util.h

@@ -28,6 +28,9 @@
 #define BPY_UTIL_H
 
 #include "bpy_compat.h"
+#include "RNA_types.h" /* for EnumPropertyItem only */
+
+struct EnumPropertyItem;
 
 /* for internal use only, so python can interchange a sequence of strings with flags */
 typedef struct BPY_flag_def {
@@ -46,4 +49,22 @@ void BPY_getFileAndNum(char **filename, int *lineno);
 /* own python like utility function */
 PyObject *PyObject_GetAttrStringArgs(PyObject *o, Py_ssize_t n, ...);
 
+
+
+/* Class type checking, use for checking classes can be added as operators, panels etc */
+typedef struct BPY_class_attr_check {
+	const char	*name;		/* name of the class attribute */
+    char		type;		/* 's' = string, 'f' = function, 'l' = list, (add as needed) */
+    int			arg_count;	/* only for function types, -1 for undefined, includes self arg */
+	int			flag;		/* other options */
+} BPY_class_attr_check;
+
+/* BPY_class_attr_check, flag */
+#define BPY_CLASS_ATTR_OPTIONAL 1
+#define BPY_CLASS_ATTR_NONE_OK	2
+
+int BPY_class_validate(const char *class_type, PyObject *class, PyObject *base_class, BPY_class_attr_check* class_attrs, PyObject **py_class_attrs);
+
+char *BPy_enum_as_string(struct EnumPropertyItem *item);
+
 #endif