Favicon support with :icon

[rmm5t]

Would an :icon option be of value to this gem? If so, I'm willing to submit a pull-request for it.

---

Defaults to "image/x-icon":

set_meta_tags icon: "/favicon.ico"

<link href="/favicon.ico" rel="icon" type="image/x-icon">

---

Supporting different mime types:

set_meta_tags icon: { "image/png" => "/images/icon.png" }

<link href="/images/icon.png" rel="icon" type="image/png">

[zrisher]

That would be useful to me, especially if it supported the sizes attribute:
sizes="16x16 32x32" or sizes="228X228"

and different values for rel:
apple-touch-icon, apple-touch-icon-precomposed to specify a precomposed version for < iOS7.

Per these sources 1,2,3, we don't need an IE statement since we can include favicon.ico in the site root at public/.

Maybe the easiest way to do this would be a hash that takes the value for each attribute?

set_meta_tags icons: [
  { href: '/images/icons/icon_96.png', rel: 'icon', sizes: '32x32 96x96', type: 'image/png' }, 
  { href: '/images/icons/icon_itouch_precomp_32.png', rel: 'apple-touch-icon-precomposed', sizes: '32x32', type: 'image/png' }, 
  ...etc...
]

We can support newer IE tiles with the existing custom tag functionality.

[rmm5t]

@zrisher Some good suggestions, but I don't really want this to be just a direct mapping to the <link> tag.

Support for apple-touch-icon is a good idea too, but I think we should just let precomposed die off. It's deprecated afterall.

[zrisher]

@rmm5t Ok agreed support for precomposed is probably unnecessary.

Supporting type is probably unnecessary too, since the only time you'd need a type other than image/png is if you're providing an ico file to non-IE browsers (which don't necessary look in root). That's a sub-optimal choice compared to giving them resolution-targeted png files that only include the necessary data for that browsing environment. I guess someone might want to use jpg's since they're smaller at larger resolutions, but they're lossy and it's unlikely to save much space for favicons.

[kpumuk]

Added in d321be1