title: Overriding an Ivy dependencies' revision
body: <p>I use Apache Ivy for handling library dependency.  In my company we have a "core" project which is released/versioned periodically.  We then have many "customer" projects which are for a particular client.  Each customer project uses a particular version of the core project which we maintain in the ivy.xml of the customer project.  All fine.</p>
  
  <p>Sometimes someone will want to change core locally and test the change with a specific project.  In that instance they will build the core and publish it to a local Ivy repo, rather than the shared one.</p>
  
  <p>In order to have this locally built version picked up do I need make sure the locally built version or core publishes with the exact same x.y.z version as the project is pointing at in ivy.xml?  Or is there some other approach?  I'd rather not have people required to fiddle with the ivy.xml (e.g. change it to core -> latest.integration) as that's the sort of change that gets checked in to source control by accident.  Maybe there's some way of overriding the revision of a dependency in ivy.xml, perhaps in a local properties file?</p>