travis config
adds dependencies
removes unused boilerblate code
sinatra-based rack middleware to handle routes to assets

only supports images, stylesheets, and javascripts at the moment
integrates Rack::ClassyAssets & Sprockets::helpers

- sinatra extension to integrate our classy_assets middleware with
  the sprockets-helpers gem
ignore .sass-cache
fix spec pattern
adds dependencies w/ pessmisstic locks on versions
dynamic assets path proved difficult

hardcoding to /assets for now
ensures the correct File object is used
dummy assets used for testing
adds basic specs for rack middleware
fix class paths for sprockets and compressors
fixes numerous issues with settings

- properly set default settings (without broken || shenanigans)
- call methods on the app instance properly
- other fixes that came out of adding specs to this extension
make rack middleware setup less verbose in test app
adds basic specs to sinatra extension