Add jekyll-assets plugin
Change directory structure to suit jekyll-assets plugin

- The plugin uses a Rails-style folder layout where the top level
  `_assets` directory will contain iamges, stylesheets and javascripts
  folders. The assets can then be referenced from HTML accordingly
Add bootstrap and uglifier gems
Use cache-friendly assets
Adjust speaker name font size in mobile sizes

- Too large a font-size would break the layout because, bootstrap.
Test out caching for github pages
Update Github jekyll config to suit jekyll-asset settings
Use compressed images for map, speakers
Merge pull request #21 from GardenCityRuby/use-jekyll-assets-that-enables-caching

This adds support for asset management