Fix formatting.

Mixed tabs and spaces throughout `jaggr-sample-dojo/pom.xml`.
Replace copy-maven-plugin with maven-antrun-plugin with overwrite set to false.
Merge pull request #186 from KenPowers/maven-3.1.0-fix

Maven 3.1.0 Fix
Merge pull request #184 from chuckdumont/master

Improve variable substitution support
Fix cachability issues