hs.menubar - Rewrite Extension to make use of modern macOS Frameworks

[latenitefilms]

As discussed in #1057, #914 and #1229 eventually it would be great to do a re-write of hs.menubar.

This should include:

• Rewriting hs.menubar to use the newer macOS NSStatusItem API (which should fix hs.menubar icons/titles are sometimes trunctated #914)
• Ability to "refresh" an already open menubar-menu (Discussed in Ability to "refresh" menubar-menu #1229)
• Support for dragging and dropping to a menubar (Discussed in Drag & Drop to Menubar #1057)
• Support for attaching a hs.webview to a custom menubar (Discussed in Drag & Drop to Menubar #1057)
• Remove priorities since they are no longer supported with 10.12+ (Discussed in 10.12 -- hs.menubar priorities (menubar placement) doesn't work #974)
• Use a hs._asm.guitk object as an attachment to a hs.menubar (Discussed below)
• Bug? hs.menubar on multiple monitor (Discussed in Bug? hs.menubar on multiple monitor #1045)

[asmagill]

• Remove priorities since they are no longer supported with 10.12+ -- 10.12 -- hs.menubar priorities (menubar placement) doesn't work #974

[latenitefilms]

@asmagill - I wonder if rather than using a hs.webview we could use a hs._asm.guitk as an attachment to a hs.menubar (i.e. to create an interface similar to Dropbox's system menubar item)?

[asmagill]

Ultimately, yes this is planned; don’t have an eta, though.

[asmagill]

FYI menubar rewrite in progress; will add with guitk in upcoming pull (needs some more testing and documentation)