ignore quoted characters when splitting keybindings into actions

[matthias314]

Currently a keybinding of the form

"F3": "command:run sh -c 'ls | wc -l'"

does not work because micro interprets &, | and , as separators between actions:

micro/internal/action/bufpane.go

Lines 103 to 105 in f49487d

	// TODO: fix problem when complex bindings have these
	// characters (escape them?)
	idx := strings.IndexAny(action, "&|,")

This PR fixes this by ignoring escaped and quoted characters when splitting a keybinding into actions.

[matthias314]

I believe the latest version addresses all comments (which I've therefore marked as resolved). Let me know if that's not the case.

[dmaluka]

LGTM. Thanks for the fix.