Update to allow the install of tomcat 7.
ServerLifecycleListener listener removed for ver 7

The Listener is no longer used in tomcat 7, so it is removed from the
server.xml configuration template for that version
refactor: move normal attrs set to recipe

Since now the normal attributes depend on tomcat version and also they
are calculated (and not configurable), it's better to put them on the
recipe.

If not, if you want to override the base_version you should also
override all the other dependent attributes.
Use node.default rather then node.set
Test for base version < rather than != 7
Move attributes back from the default recipe to cookbook defaults
Update author info
Merge pull request #20 from b0d0nne11/tomcat7-support

Tomcat7 support