applied patch #254 to allow skipping of ExDLL using SKIPPLUGINS

git-svn-id: https://svn.code.sf.net/p/nsis/code/NSIS/trunk@6544 212acab6-be3b-0410-9dea-997c60f758d6
fixed bug #1098 so test-code works on ubuntu now

git-svn-id: https://svn.code.sf.net/p/nsis/code/NSIS/trunk@6545 212acab6-be3b-0410-9dea-997c60f758d6