Merge pull request #6 from rnc/master

Improve documentation. Refactor versionOverride to two supported formats...
Add a modified-by to the top level pom. Improve manifest information
Merge pull request #7 from rnc/master

Add a modified-by to the top level pom. Improve manifest information
refactor EffectiveModelBuilder into ModelOverridesResolver, and make it a component instead of a singleton. This has a side effect of making it much more consistent with the way the rest of the extension executes.
oops, missed the remote repositories list field in the ModelOverridesResolver...left over from when it was a singleton.
Fix extraneous output after multiple runs of the extension. Upgrade to current JDOM 1.1.3