Adding comments for basic expression operations.
More comments.

Updating sphinx documentation and trying to cleanup comments.
Merge pull request #57 from spartan-array/comments

Comments
finish random forest classifier
change travis.yml and add some comments
change .travis.yml from sklearn to scikit-learn
add comments for more thant one tree will be built per kernel call
Merge pull request #59 from EasonLiao/sklearn_rf

finish random forest classifier
Merge branch 'master' into comments