Build for scala 2.11

Hi,

  I've build widgets module for Scala 2.11. Could you please integrate? In addition I removed unnecessary dependencies and upgrade sbt, log4j and logback to the latest versions.
Hi, the way we publish modules is we use +publish, for that to work, sbt looks at the values from `crossScalaVersions` and compiles/test/publishes for each of those versions.

Since scala 2.10, the scala team made the promise that minor versions are binary compatible, so you don't need 2.10.4 and 2.10.0 in the list, you just need 2.11.1 and 2.10.4 (but you do need 2.9.2, 2.9.1, 2.9.1-1 becuse back then, binary compatibility was not happening.)

So, please just have one 2.10.4 and add 2.11.1