Allow empty parentSelector

[stefanotorresi]

This patch builds on #218, which supersedes, because it wasn't handling all the cases.

This fixes #239, angular-ui/ui-router#2260 and #179 by appending the bar to the body tag when the specified selector (if any) is not available. The check happens when start() is invoked, so as soon as the selector is ready it will be used, without involving $timeout or such things.

[furyscript]

When this fix is merged into master?? Actualy this commit can fix this: angular-ui/ui-router#2260 and #239 ?

[jklaus]

I have resolved the issue caused by the parentSelector implementation in pull 272. Feel free to pull from me.

[chieffancypants]

merged in #272

[stefanotorresi]

Honestly, I don't think #272 actually resolves the issue this PR is about.
This PR replaces find usage with querySelector, which makes the selector more usable, and it uses body as a fallback selector.
Besides that has no tests so there is no way to know... :p

[chieffancypants]

@stefanotorresi querySelector doesn't have great support in older IEs, which I still have an obligation to support.

[stefanotorresi]

Correct me if I'm wrong, but querySelector browser compatibility goes as far as Angular's.

[jklaus]

@chieffancypants, out of curiosity how far back are you having to support? My company just recently moved from IE8 to current (adding Chrome & FF) ... finally.

[chieffancypants]

@stefanotorresi Yes, technically, but with work, you can get the 1.2 branch to work with IE8, which is what I've been doing. Perhaps we could rewrite the PR to use querySelector if available, that way assholes like myself supporting shitty browsers can still use find, but you cool kids can use all your fancy tricks.

@jklaus: We're still IE8. This should change very soon though, since MS has dropped support for it. My customers are all large enterprises, so they inevitably refuse to upgrade even when there is significant pressure to do so.

[stefanotorresi]

@chieffancypants all right then, I'll update the PR right away to make it more old-browser friendly :)

[faceleg]

@chieffancypants approve?