Added correlation(), moment(), cmoment() in rv_interface.py
Fixed whitespaces
Rewrote variance, cmoment and skewness in terms of moment
refactor variance and skewness with cmoment

This requires changing some tests around so that they are less
sensitive to the exact form.

I also had to skip a couple (doc)tests
Added smoment() and refactored skewness()
Added better test-cases, removed bad ones
Issue #3275 : Added methods to Rotation class for apply to act on states

Methods have been added along with the tests to the Rotation class for qapply to act on the spin states.
Merge pull request #1834 from amitjamadagni/master

Issue 3275: qapply Rotation to spin states
Merge pull request #1875 from ankit-maverick/add_moment_and_cmoment_to_statistics.PDF

Added correlation(), moment(), cmoment() and smoment() in rv_interface.py
Add Ankit Agrawal to AUTHORS/aboutus

Welcome to SymPy!
Merge pull request #1892 from mrocklin/ankit-authors

Add Ankit Agrawal to AUTHORS/aboutus
Test a bug in ask.
Patch a little bug in ask.