Formatting and cleanup

* Tabbing in web.xml files and removed auto-generated tag
* Tabbing in other files
* Renamed gae.version to more popular appengine.target.version in pom.xml
Get mvn appengine:devserver working again

* Added dependency on appengine-endpoints as we use that sort-of now
* Switched devserver to deploy as debug for attaching to
Switch default deploy target to be attendance-dev
Bump appengine target version to 1.9.9
Merge pull request #259 from curtisullerich/bump_appengine_version

Bump appengine version