Random SRG class and Aggregator class.
Merge branch 'master' of github.com:BNUCNL/region-growing-froi

Conflicts:
	algorithm/region_growing.py
Rename some class to be consistent with PEP8 and adjust the position of the main SRG class and some parameters.
Merge pull request #15 from zhouguangfu/master

Random SRG class and Aggregator class.