Improve tests

[shawninder]

This could eventually double as a feature list for the docs..

• bundling
  • js bundle
  • js source maps
    • inline
    • none
  • css bundle
  • css source maps
    • inline
    • file
    • none
  • cyclical requires
  • cyclical @imports ?
  • commented requires and @imports
  • transform runs only where configured
  • apply transform globally with -g
  • onComplete called only once everything is done
  • Works when postcssify is installed globally
• Watching: all of the above +
  • rebundling
  • adding/removing requires or @imports
• Deving: all of the above +
  • budo
  • beefy
• Building: all of the above +
  • minification (uglify-js, cssnano)
• Linking: all of the above +
  • linked (nested)
  • not linked
  • half linked