Added stuff

+ updated .gitignore (*.class)
+ added main class to build.sbt
+ added run script (convenience)
+ added hello-akka example
Updates

+ Spelling errors in README.md
+ added Actor file
+ deleted Actor worksheet
Added supervisor example

+ Actor_6_2.scala
Added remote-actor example

Not _really_ remote, but close enought to get the point
Updates

+ Moved futures to sala files
+ added new future scala file from scala dist-examples
+ modified list of things not covered
Updated None/Null/Nill example

+ Added Nothing as well as comment to checkout Nil object (for a look
  at how Nothing is useful)
Updated README.md
Cleanup

Just some formatting cleanign for the various worksheets.
Updated README.md

Added some information about how to run the Future/Actor examples