Ignore execution of dependency-plugin in M2E
Add xmvn-subst module
Move beust-jcommander dependency up to xmvn-tools
Remove custom logging cruft

Previously there was a mixture Plexus logging (used when inside maven)
and of home-made console logger (used when running as a tool, outsides
of Maven).

With this commit custom logger is removed completely and code is
migrated to rely exclusively on Plexus logging.  This means that tools
will have to use Plexus and customize the logger if needed.
[xmvn-resolve] Properly configure Plexus logger
[xmvn-resolve] In classpath mode assume artifact type is jar
Implement xmvn-subst
Include xmvn-subst in assembly