Upgrade to gradle 1.4
Enable Sonatype publishing

This change moves us towards being able to publish to Maven Central.  It
contains a number of build changes:
* Enable the maven plugin in the java projects.
* Enable javadoc and source jar generation.
* Enable artifact signing.
* Enable uploading to Sonatype repositories.
Include osmosis prefix on project names

All artefacts have an osmosis prefix, however the project names were
named without the osmosis prefix.  This causes some confusion when
trying to publish to Maven because we end up with an artefact name
including osmosis, but a project name not including osmosis.  It seems
simpler to rename all projects to include the osmosis prefix.
Include SNAPSHOT suffix on build versions by default

Update builds to have a SNAPSHOT suffix on their version numbers by
default.  This aligns with the Maven version numbering conventions and
is necessary to publish to SNAPSHOT repositories.  Release versions will
have a RELEASE suffix, and this is set by overriding a build type
variable at build time.