feat(gitignore): add gitignore file
fix(): remove non-functioning file reroute
feat(): add an express server for the example
feat(): add support for pdf zoom settings

- Adds a set of standard pdf zoom levels. 'page-actual', 'page-width',
  'page-height', 'page-fit', or a percentage are acceptable
- Adds a zoomLevel attribute to pdfviewer directive
- Adds a changeZoom method to PDFViewerService
feat(): add use of new zoom features to example
feat(): add info for version 0.3.0