2017 07-24 
	* updated runit.partiallymatched.R due to continuity correction
	implemenation changes

2017 07-24 
	* fixed a bug related to continuity correction in pm.wilcox.test related
	to U.mw, U.p, U.3 and U.4

2018 09-19
	* add MW-MW_2 and SR-MW_2
	* add choose.test
	
