Add build.properties to explicitely specify sbt version
Add sonatype publishing info, allows to run publishSigned

Following http://www.scala-sbt.org/0.13/docs/Using-Sonatype.html.
Fix organization to point to a domain name.

This assumes, that chrisomeara.com is owned by Chris O'Meara (which
is usually required by sonatype)
Update datastax and scala version
Add cross publishing for scala 2.10 and 2.11.

argot and scalatest had to be updated for this. For argot there's not
yet a publicly available build for scala 2.11 (see bmc/argot#11), therefore
for now I've published it to my bintray repo. As soon as argot is
available for 2.11 in maven central, the argot version can be updated
and the resolver for bintray can be removed.
Merge branch 'magro-sbt-sonatype-publishing'