Windows shell integration system settings

[damieng]

This is the Atom side of atom/settings-view#811 that provides the parts necessary for that one and facilitates;

1. Only installing the file handler by default (no more context menus by defaut but you keep them if you already have them)
2. Allows side-by-side of Atom.exe and AtomBeta.exe which can set, unset and upgrade independently

[lee-dohm]

Is there a reason to use fat arrows for these functions?

nit It is typical to have a blank line between functions.

[damieng]

The fat arrows are required so that the @ operator points to this object not to the window when the callback functions are executed.

I can add spacing.

[Ben3eeE]

Allows side-by-side of Atom.exe and AtomBeta.exe which can set, unset and upgrade independently

Do we know when this is set to release? As in which beta version would be the first I can install side by side with stable? I am very interested in some 1.10 features but wouldn't want to lose safety of a stable install on main workstation.