Fix scriptplugin causing massive cpu load and slowing everything in the client down.
(Related: 118a2c05026183901cbc01a9452b0e47822bcbe1)

Fixes-Issue: CLIENT-418
Change-Id: I3b50c2cc10ec8428b2729b7e86feda01e076100d
Reviewed-on: http://gerrit.dmdirc.com/2962
Reviewed-by: Chris Smith <chris@dmdirc.com>
Automatic-Compile: DMDirc Build Manager