Auto-update functionality

The auto-update system is coming along and will alleviate concerns about getting bug-fixes and new features out to users as painlessly as possible. After v1.20a is released I'll utilize the mass-email function on itch.io which will allow me to notify customers of a new version they can download as I'm sure that at least half have just been using the same version they downloaded when they originally paid for it and haven't been back here or bothered with following development. I can't blame them, they've got more important things to do!

At any rate, once they download the latest version they can continue ignoring development and still be able to stay current on updates automagically, which will be a relief to me personally, as I believe that paying customers should be afforded the best service and software I am capable of.

So far everything is in place for checking if the version of PixelCNC that is running is the latest available version and downloading the update package file. The last piece of the puzzle left is writing the simple little utility that PixelCNC will launch after downloading and unpacking a new version into a temporary folder which will be responsible for copying all the new files over the existing installation, which will require running as an administrator (via a .manifest resource compiled into itself, IIRC) 

Thanks for reading!