Use @property decorator instead of property function

[rahulporuri]

There are a few places in the codebase where we use the old style property(...) to define getters and setters for properties - which we can now replace with the @property decorator.

chaco/chaco/shell/plot_window.py

Lines 90 to 91 in d7885d5

	# This is a Python property because this is not a HasTraits subclass.
	container = property(get_container, set_container)

chaco/chaco/shell/plot_window.py

Lines 210 to 211 in d7885d5

	# This is a Python property because this is not a HasTraits subclass.
	container = property(get_container, set_container)

chaco/chaco/tests/test_speedups.py

Line 58 in 3de7780

func = property(_get_func)