bug fix for python 2 compatibility

support scipy csr sparse matrix and fix pip install bug

Official version v0.1.4

version 0.1.3

HierarchicalSampling and update author list

Merge pull request #107 from ntucllab/v0.1.3b0

version 0.1.3b0

support python2 and pylint code checker

version 0.1.1

Merge pull request #30 from ntucllab/interface-documentation

Update interfaces.py documentation