Auto-updater

[joevenzon]

Do we want to provide libcurl headers + dll for windows or let the guys compile it by themselves?

I recall libcurl being pretty easy to build, so I say let people build it for themselves if they want to compile on windows.

The main function in unittest.cpp might cause problems for MacOS guys. They are compiling everything in the src directory.

That wasn't my change, that was from thelusiv adding unit tests as a build step.

The gup thingy is windows only?

Yep. All it does is check to see if a new exe installer is available, downloads and auto-runs it.