icon size change updates icon.
Mention core-icons import in docs
Docs: remove @extends
add css-sizable mode to core-icon; activate using size=""
update size only if truthy
rename metadata
update component page link
pinting the link to icons demo
Color core-icon to the surrounding text color

Fixes #4
Merge pull request #5 from devnook/master

pointing the link to icons demo
Mention non-default built-in iconset import

If you want to use the non-default built-in iconset, you'll need to include an import for the relevant iconset. This was missing in the docs.
polymer.html should be included in the element level, not in the app level
Merge pull request #9 from zenorocha/patch-1

polymer.html should be included in the element level, not in the app level
core-icon is now sizable via css height/width and no longer supports the size attribute. Fixes https://github.com/Polymer/core-icon/issues/8
remove size attribute
Merge pull request #7 from leonderijke/patch-1

Mention non-default built-in iconset import
Add aria and alt support to core-icon