Improve the viewfile macro experience

The viewfile macro could use some love. Some of the areas of improvement:

• It takes a while to convert the files in the background - you see an annoying message to wait while its loading.
• It's still flash - we could switch this over to a HTML5 implementation
• User experience - the design could use a bit of a refresh as well
• Editor placeholder experience. If you are in edit mode, we could load the first slide and use that as a rendered placeholder image.
• Also take a look at the Office Connector - View File component on JAC and see what other little improvements we could do.