Move to JDK1.6

It turns out that there are a number of dependency upgrades we can't do until we move completely to jdk1.6, such as going to jetty 7, tomcat 7 components, axis 2.x, etc. In addition, certain connectors already require jdk1.6 (the alfresco connector, for instance). Other dependencies must be built by us in order to get a jdk1.5-compatible version.

Since jdk1.6 has been end-of-life'd, it may be the time to make this move.