Change xtend.version in POM files

I have tried to run the XtendFx build “mvn clean install” on a computer with an empty Maven repository. 

In my opinion the xtend version, defined in the properties, need to be changed:
     <xtend.version>2.4.2-SNAPSHOT</xtend.version>

It should be “2.4.2” without SNAPSHOT, because the SNAPSHOT is not available if you don’t have built xtend locally.

The ${xtend.version} should also be used for the artifactId: org.eclipse.xtend.standalone