[popover] [tooltip] mixin

[tmorehouse]

Moved common functionality + tether into popover.js mixin.

This will help auto documentation so that only applicable props are shown in each component's docs.

Currently b-tooltip docs list a lot of props that are only applicable to b-popover, so this will help prevent some usage confusion such as issue #467 (#467 (comment))

This PR replaces outdated PR #470, so that it incorporates changes from PR #485 which addressed issue #484

[alexsasharegan]

Looks like it's just a solid move to mixin vs. extends. 👍

[tmorehouse]

Yep... using a mixin will hep with the auto-documentation generation of supported props on both tooltip and popover.

[alexsasharegan]

It looks like you also try to structure the order of template props (I've been on a mission to make my own ordering consistent). I wonder if there is a style guide for this yet. I've been working in this order more or less:

• v-directive
• id, class, other std html attrs (with bound attrs coming second)
• event handlers

I imagine that's something the Vue community will eventually settle on. That and little things like closing the opening markup tag on the same line or a new line.

[tmorehouse]

Yeah, I find having the events last makes things easier to see, and bound stuff near the first. The closing markup tag on a newline helps show the end of attributes/bindings/events as sometimes they line up with the next child element

[alexsasharegan]

We could probably use a standard set of Vetur formatting settings to keep things consistent. What editor do you use when working with Vue code?

[tmorehouse]

I'm old school and use either the github web interface, or or larger changes I edit in notepad++ :P

[alexsasharegan]

[tmorehouse]

I use vim as well ;-) (and vi if no vim)

[alexsasharegan]

I've managed to get as far as learning how to quit vim—and I feel accomplished there!

[tmorehouse]

Any objections to this PR being merged?

[alexsasharegan]

None from this guy. Onward!