Introduce debug property for managed containers

It's currently too tedious and inconsistent across managed containers to enable debugging with the VM set to suspend on startup. This task requires hacking on the VM arguments, which is too low level for casual users.

Managed containers should offer a configuration property named "debug" that will enable the proper JVM switch to enable debugging with the VM set to suspend on startup. The suspend flag, of course, gives the developer an opportunity to connect the debugger before the tests begin executing.

We can either make the debug flag a boolean or we can make it a three state toggle: true, suspend, false. In the latter case, a value of true enables debugging but not suspend, a value of suspend enables debugging and suspend and a value of false disables debugging.

This should be implemented for the following containers:

JBoss AS 5 - 6
GlassFish 3.1
Tomcat 6 - 7

An issue needs to be filed in the JBoss AS 7 issue tracker after this issue is resolved (so that we settle on the "standard" before lobbying for the feature in AS 7).