Add an EDT handler invocation.

This allows MBassador handlers to be executed nicely on the EDT.

Change-Id: I2b7e843584ef5e698e078cc891b9ff25836ce9a3
Reviewed-on: http://gerrit.dmdirc.com/3795
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager
YAY JVM Bugs.

Change-Id: Iaddfb3e7bd81f9dc6124e3fba483262c405d87d7
Reviewed-on: http://gerrit.dmdirc.com/3794
Reviewed-by: Chris Smith <chris@dmdirc.com>
Automatic-Compile: DMDirc Build Manager