fix copy/paste of non-http links in Notes

Hi, 
copy+paste within notes removes non-http links. So the html code `<a href="zotero://select/items/0_DQHBAGPE">link</a>` becomes `<a>link</a>` when I copy and paste it within notes. http links, however, work without a problem. It's probably some obscure tinymce bug. It works in Chrome but it doesn't in firefox. This pull request fixes the bug with a small addition in the paste plugin. I had to replace the minified version with the full one and then changed the part which is earmarked with an `// Added by Zotero`.