Merge pull request #801 from jseabold/docs-cleanup

DOC: Fix ANOVA section titles
BUG: Use two- not one-sided t-test in t_test. Closes #740.
TST: Test SVD convergence failure due to bad start params.

TST: Add test
ENH: Check for bad values from start_params for ARMA. Closes #675. Closes #15.

BUG: Include all AR params
STY: Remove comment
BUG: Use correct definition for root checking.
Merge pull request #803 from jseabold/fix-arima-error-msg

ENH: Fix arima error message for bad start_params
ENH: Import formula.api in statsmodels.api namespace.
Merge pull request #806 from jseabold/formula-api

ENH: Import formula.api in statsmodels.api namespace. Closes #804.
Merge pull request #802 from jseabold/two-sided-ttest

BUG: Use two- not one-sided t-test in t_test. Closes #740.
ENH: Add files to convert inputless ipynb->rst
DOC: Add notebook files from tutorial
DOC: Update Makefile to build ipynb files
DOC: Add CSS modified from nbviewer.
DOC: Skip notebook files in restify examples.
DOC: Make sure to hash the right filename
DOC: Update titles
DOC: Add notebook examples to docs
DOC: Handle title separately for sphinx
DOC: Do not run nbgenerate if paths need updating.