misc py/rna changes

- running a script from a file now uses the PyRun_File(FILE *, ...) rather then PyRun_String("exec(open(r'/somepath.py').read())"...), aparently FILE struct on windows could not ensured to be the same between blender and python, since we use our own python on windows now it should be ok.

- generating docs works again (operator update for py style syntax broke them)

- python operator doc strings was being overwritten

- added rna property attribute "default" to get the default value of a property, not working on arrays currently because variable length arrays are not supported.

source/blender/python/intern/bpy_interface.c

@@ -260,10 +260,16 @@ int BPY_run_python_script( bContext *C, const char *fn, struct Text *text, struc
 		py_result =  PyEval_EvalCode( text->compiled, py_dict, py_dict );
 		
 	} else {
-		char pystring[512];
-		/* TODO - look into a better way to run a file */
-		sprintf(pystring, "exec(open(r'%s').read())", fn);	
-		py_result = PyRun_String( pystring, Py_file_input, py_dict, py_dict );			
+		FILE *fp= fopen(fn, "r");		
+		if(fp) {
+			py_result = PyRun_File(fp, fn, Py_file_input, py_dict, py_dict);
+			fclose(fp);
+		}
+		else {
+			PyErr_Format(PyExc_SystemError, "Python file \"%s\" could not be opened: %s", fn, strerror(errno));
+			py_result= NULL;
+		}
+		
 	}
 	
 	if (!py_result) {