Fixed debug overriding
Calling the setJvmArgs() method scans the provided arguments for a pattern matching the debug flags; if it finds them, it sets debug to true and removes the arguments. If it does NOT find them, it sets debug to false. Thus, in order to allow the previous debug setting to remain after setting new jvmArgs, we have to store the previous value of the getDebug() method and set it again afterwards if necessary.

Conflicts:

	src/main/groovy/org/grails/gradle/plugin/internal/GrailsLaunchConfigureAction.java
Fixes #6