Update 'attributes' for current standards

`mathics.builtin.attributes`:

* apply -> eval
* Add WMA links add
* Class names ordered alphabetically
* Hard breaks in docstring removed
* Some incorrect references to "leaves" changed to "attributes"

`mathics.core.attributes`:

* Add short comments above flag value

Author: rocky

Makefile

@@ -112,7 +112,7 @@ clean: clean-cython clean-cache
 
 #: Run py.test tests. Use environment variable "o" for pytest options
 pytest:
-	py.test $(PYTEST_WORKERS) test $o
+	$(PYTHON) -m pytest $(PYTEST_WORKERS) test $o
 
 
 #: Run a more extensive pattern-matching test