added special section for Mac users as well as mention "make slides" (wescpy)
Merge pull request #67 from nyergler/wescpy

Wesley Chun documentation fixes from PyCon sprint
Removing absolute positioning from h2 (fixes #37).

This alleviates the most glaring issue with positioning when printing
slides to PDF that use the base themes.
Run Jasmine tests when testing under tox.
Add note about CSS change (#37) to NEWS.