autopep8 --ignore=E501 fixes. Marginal improvement.
Merge remote-tracking branch 'cam/master' into chap3-style

Conflicts:
	Chapter3_MCMC/IntroMCMC.ipynb
Ending code cells with a semicolon.
Merge pull request #180 from eli-b/chap3-style

autopep8 --ignore=E501 fixes. Marginal improvement.
Revert "Ending code cells with a semicolon."

This reverts commit 4876681e129683b32b1ad5484360b70e47b6121c.
edits to ch3