Add option to disable automatic updates check & install

[i0xHeX]

Currently, if there is a newer version, it doesn't ask you what you want to do with it, whether to install it or discard it. It always installs a new version, and that's kind of annoying if you can't handle it. This even happens when you run a portable version, so it will install a new version every time you run it.

Adding options to disable the automatic update check and automatic install (and making the last one disabled by default) is a good solution.