Nodes Editor + other warning fixes:

* Added 'active node' panel for the Nodes Editor. This panel, in the NKEY region, shows the settings for the active node. Included in this panel is a field used for editing the unique-name of the node too. 

* Fixed a number of uninitialised vars warnings that I missed in previous commit...

source/blender/python/intern/bpy_operator.c

@@ -153,7 +153,7 @@ static PyObject *pyop_as_string( PyObject * self, PyObject * args)
 	int all_args = 1;
 	int error_val= 0;
 
-	char *buf;
+	char *buf = NULL;
 	PyObject *pybuf;
 
 	bContext *C = BPy_GetContext();