Merge pull request #11 from rampart81/master

#10 main.scala 리팩토링
Allow to serve static files. This fixes #9.
cache: Handle Last-Modified and If-Modified-Since.

This solves #13.
Add missed HttpConstants.scala.
Chunked encoding support
removed build.sbt and added Build.scala to customize build settings and sbt prompts
Adeed scala test dependency
test for Enumerator
added akka test kit dependency