iFit/sw_update

 updates the SpinW installation from the internet

 SW_UPDATE()

 {onlineRev} = SW_UPDATE(installDir)

 sw_update creates a new folder with the latest release beside the current
 SpinW installation and add the new version to the working path (and
 removing the old one).

 Input:

 installDir    Folder name, where the new version is installed. Default is
               the parent folder of the current version of SpinW. If
               installDir == '.' update will be installed to current
               folder.

 Output:

 onlineVer     If output is expected, the revision number of the online
               SpinW is given. Optional.