Initial commit of upgrade to metrics 3.0.1
Clean up BuildConfig for the example app.  Remove unneeded deps.
Adding back some convenience classes (Metrics and HealthChecks) to make upgrading easier and first attempt at having the plugin make application specific registries available globally.
Add some more convenience methods to Metrics and refactorings
Refactorings and make the units for the metrics servlet configurable
Remove 'yammer' from package names
Use grails wrapper
Update version to 3.0.1-1-SNAPSHOT
Add plugin.xml and the plugin zip file to .gitignore
Add a config option to turn off prepending class names to metric names
Remove unneeded function
Removed unused logging code and got rid of the specialized Timer.groovy class
Install grails wrapper for the example app
* Bump version to 3.0.1-2-SNAPSHOT
* Use static singleton registries instead of dynamically creating them during plugin initialization
  to avoid problems with ordering if using metrics within other plugins.
Update documentation for release. Set version to 3.0.1-2.
Merge pull request #18 from jeffellis/3.0-upgrade

3.0.1 upgrade