Added center and frame arguments for pie-charts
Added test for frame and center arguments on ax.pie()
Fixed pep8 conformance
Improved interaction of center and frame arguments
Added missing baseline image for pie chart test
Merge kpalin:v1.4.x to master.  Added pie kwargs

ENH : add center and frame kwargs to pie

Conflicts:
	lib/matplotlib/tests/test_axes.py

whitespace conflicts