#5: Delegate VBOX restart to INNOSETUP

Sometimes VBOX will automatically restart on a silent install. We should suppress this by default in the msiexec command since INNOSETUP will prompt for a restart in non-silent mode appropriately and we can control the restart of silent install in the normal way at the boot2docker-install.exe level ala 

    boot2docker-instal.exe /SP /SILENT /VERYSILENT /SUPRESSMSGBOXES /NOCANCEL /NOREBOOT /NORESTART /CLOSEAPPLICATIONS /LOADINF="b2d.inf"'

There must be some weird end of line funk between unix and windows causing the entire replacement of this file but i wasn't able to get sublimetext to comply with whatever end of line usage is happening in this repo by default. The key line being changed is only
```
 -    if Exec(ExpandConstant('msiexec'), ExpandConstant('/qn /i "{app}\VirtualBox-4.3.12-r93733-MultiArch_amd64.msi"'), '', SW_HIDE,
+    if Exec(ExpandConstant('msiexec'), ExpandConstant('/qn /i "{app}\VirtualBox-4.3.12-r93733-MultiArch_amd64.msi" /norestart'), '', SW_HIDE,
```