Adds option to use ST 3 new tooltips

[subhaze]

Adds tooltip support for ST 3, if a URL or doc is available, it shows that as well.

As of right now this will only work on the very latest ST 3 dev build (3070)

[marijnh]

Can we feature-detect tooltip support by checking whether show_popup exists in view, and make that the default if supported?

[subhaze]

@marijnh Sure, I'll update the patch in a bit.

[lukasbob]

Played around with this and it looks great! Might need better handling of long URLs, though. These cause the content to expand so it overflows the 600px width of the tooltip, obscuring some of the content. The screenshot below shows this:

[marijnh]

I wasn't able to test this myself yet, since I don't have a Sublime Text key, but the code looks good, and I've merged it. I made a small change in 1afc929. Please verify that that also works on ST3.

[subhaze]

@lukasbob OS X has the ability to scroll to the overflow, however, I've seen reports to the ST developer where it's not possible on other platforms. Future updates to ST 3 should resolve this.

@marijnh I've added a comment to that code change.