auto-load library JS using sprockets

added coffee script gem
converted application.js and line-chart.js to coffee script
added source map for js libraries

added server start command

refactored currency page to use LineChart coffeescript

added javascript example pages
- expand rectangle width by dragging
- changing fonts to red by mouseover

renamed file and path
added scroll progress bar example

Email sent notification should be after the actual mailing action

turned off TLS on localhost mailing

removed rbx-2 in travis
Merge pull request #60 from bonniecpk/auto-load-assets

auto-load library JS using sprockets