FIXED fplot.plot() to display 2 or 3 subplots as needed
FIXED experiment.Pulling.plot() bug and added testcases

If trying to plot a pulling experiment before fitting, would throw
an error. Fixed up experiment.Figure class and usage which abstracts
out matplotlib calls (in case I want to move to Chaco.)
	modified:   experiment.py
	modified:   test/testCurveFit.py
	modified:   test/testExperiment.py
	modified:   test/testFileIO.py