Added System::Call direct register memory access type


git-svn-id: https://svn.code.sf.net/p/nsis/code/NSIS/trunk@6505 212acab6-be3b-0410-9dea-997c60f758d6
InitiateShutdown is used to reboot the machine if available (patch #247)


git-svn-id: https://svn.code.sf.net/p/nsis/code/NSIS/trunk@6506 212acab6-be3b-0410-9dea-997c60f758d6