Merge pull request #3 from zhouguangfu/master

remove ClassTest.py
prilimilary try to add average contrast
Merge branch 'master' of https://github.com/BNUCNL/region-growing-froi
add average contrast to the library
add peripheral contrast to the library
add a kind of fixed threshold grow to the library
add 4d region growing
Merge pull request #5 from liuzhaoguo/master

add 4d region growing
Merge branch 'master' of github.com:BNUCNL/region-growing-froi