Linux: VirtualBox binaries can now be started from directories other than the installation directory

VMM: added support for PAE guest mode

VMM: added support for hosts running in NX (No Execute) / DEP (Data Execution Prevention) mode

Graphics: fixes for dynamic resolution handling

Linux module: yet another kernel panic fix due to weird patches in RedHat Enterprise Linux 4 Update 2

VBoxSVC: if VBOX_USER_HOME is set, look for configuration in this directory (default: $HOME/.VirtualBox)