Refactoring to use the paper-button-base and remove the deprecated paper-focusable dependency.

Fixes #61
Fixing the styling of signed in but need more auth.
Updating reference to the google-apis component and adding author.
Merge pull request #62 from Zoramite/paper-focusable

Refactoring to use the paper-button-base and remove the deprecated paper...
Fixed typo
Merge pull request #63 from pborreli/patch-1

Fixed typo
Update to poly 0.5.1
revert version bump
Merge pull request #64 from GoogleWebComponents/update

Update to poly 0.5.1
Fix Apache-2, add authentication keyword
Style tweaks for consistency