adding GUI similar to pdf.js

[intellisense]

With this pull request the user will have a topbar navigation to perform following actions:

• Toggle sidebar (toggle side bar button only shown if there is outline)
• Next/Previous button for navigation
• Jump to page
• zoom in and zoom out buttons
• full screen (presenation mode option)

If user is going to scroll then the page number and outline will be updated/highlighted automatically.
The navbar.js must be included after pdf2htmlEX.js has been included and initialized hence the use of variable pdf2htmlEX inside navbar.js is implicit and clousre compiler raised warning (which we can ignore I guess?)

Final result look like this:

[intellisense]

To adjust the fixed top bar nav height.

[coolwanglu]

Thanks for the PR, I knew that some (individual) users would like a default viewer, but seems that most users are embedding the output of pdf2htmlEX into their own pages.

The changes in this PR seem intrusive, the output can no longer be embedded this way, and there are likely to be conflicts in CSS rules as common names are used.

It would be best to make an options for this.

[muthugp]

Hi Aamir,
I would like to try your GUI with PDF2HTMLEx output.
I am using Windows build downloaded from http://soft.rubypdf.com/software/pdf2htmlex-windows-version

What should i do to see your GUI and access to navbar.js?

Thanks.

[intellisense]

Hi @muthugp I am not sure what has to be done about windows build, sorry.