more useable REPL with jline 1.0

REPL with editline support using jline 1.0. (see issue https://github.com/MoeOrganization/moe/issues/38)

First, I tried to use svatsan's code using jline2 (from the extra-y-stuff branch). It almost worked, except for one problem. Upon exiting from moe> prompt to sbt, the character echo wasn't being turned back on. I couldn't fix it, so I tried going back to jline 1.0, which didn't have this problem.

http://www.scala-sbt.org/release/docs/Detailed-Topics/Forking was helpful in updating sbt configuration.