Remove compass-boilerplate and inherit font

• #172 - Make Travis badge only track master branch and add Ember Observer badge
• #175 - Use font-family: inherit; instead for font-family: sans-serif; for tooltips and popovers.
• #177 - Remove the compass-boilerplate dependency, which was causing the test suite to fail unexpectedly. This change only affects the dummy app.
• #178/#179 - Add postcss to the dummy app to replicate some of the cross-browser compatibility previously provided by compass-boilerplate