draw_marker_at_points missing return type in EnhancedAbstractGraphicsContext

[corranwebster]

In the stub for the ABC here:

enable/kiva/abstract_graphics_context.py

Lines 647 to 663 in 2ce5387

	@abstractmethod
	def draw_marker_at_points(self, point_array, size, marker=SQUARE_MARKER):
	""" Draw a marker at a collection of points
	Parameters
	----------
	point_array
	An Nx2 array of x,y points
	size
	The size of the marker in points.
	marker
	One of ``NO_MARKER``, ``SQUARE_MARKER``, ``DIAMOND_MARKER``,
	``CIRCLE_MARKER``, ``CROSSED_CIRCLE_MARKER``, ``CROSS_MARKER``,
	``TRIANGLE_MARKER``, ``INVERTED_TRIANGLE_MARKER``,
	``PLUS_MARKER``, ``DOT_MARKER``, or ``PIXEL_MARKER``. Each is
	defined in :py:mod:`kiva.api`.
	"""

This should mention that it should return a success code based on whether it can render the specified Kiva marker type (in particular, NO_MARKER should return a false-ish value).