add chi-squared test to GrammarTest, but p-values are near 0 every time
add chi squared sample file to test the chi squared functionality of scipy
minor bugfix in GrammarTest.py
Modified __eq__ in FunctionNode and its test in test/FunctionNodeTest
Merge branch 'master' of https://github.com/sa-/LOTlib

Conflicts:
	LOTlib/Examples/FunctionNodeDemo.py
	LOTlib/FunctionNode.py