Update asset_tag_helpers.rb

Escape ampersands for validation.
Merge pull request #1139 from nybblr/master

Fix invalid markup in mail_to (ampersand not escaped)
Add css id into button and link (i need this to work well with padrino-integration)
Merge pull request #1141 from WaYdotNET/fix-integration

Add id into button and link
Hide _id when using mongoid.
Revert "Merge pull request #1141 from WaYdotNET/fix-integration"

This reverts commit 4e7c44ba339660c403e0f0782ce1b1390ce8d492, reversing
changes made to b5a455e8735be2fdaa51022a34ae62340651da16.
Merge remote-tracking branch 'upstream/master' into fin-admin

* upstream/master:
  Revert "Merge pull request #1141 from WaYdotNET/fix-integration"
  Add css id into button and link (i need this to work well with padrino-integration)
  Update asset_tag_helpers.rb
Merge remote-tracking branch 'upstream/finalize-admin' into fin-admin

* upstream/finalize-admin:
  Hide _id when using mongoid.