Improvements
- [#701] - [external-link-target] seems to be broken
- [#702] - Fix external-link-target bug
- [#688] - Issue #478 IE
- [#478] - Support on IE & Edge
- [#724] - Doesn't compile with pdf.js 2.6 and pdf.js 2.7
- [#717] - Module x has no exported member 'PDFDocumentProxy'
- [#715] - Several errors while building app with --prod flag