Remove backwards compatibility imports in chaco.api

[rahulporuri]

chaco/chaco/api.py

Lines 149 to 152 in c758a65

	# Importing various symbols into the Chaco namespace for backwards
	# compatibility. New code should directly import from Enable.
	from enable.base_tool import BaseTool, KeySpec
	from enable.markers import marker_trait

[rahulporuri]

This will be an easy change to make - and an easy fix to make on the part of our users - but i am unable to search easily who imports these from chaco.api.

[rahulporuri]

closed in #679