Multiple Fixes

[christopher-besch]

• closes remove juxtapose.js watermark #5
• closes load resources locally, not from CDNs #7
• closes use jinja2 to save HTML in seperate file #8
• closes stop double and tripple loading stylesheet and javascript #10

This is a work in progress, I'll work on it whenever I find some time.

[christopher-besch]

The newest version of juxtapose.js has to be used because the undocumented callback doesn't get called on the last release.

[christopher-besch]

Actually the latest release does work, the "latest" release on GitHub is only from 2014 for some reason. So using v.1.2.2 is ok.

[christopher-besch]

@kolibril13, could you take a look at this? The CSS is currently missing so the images are way too large; I'll fix that later.

[kolibril13]

Thank you a lot for these changes!
That is a great improvement, and I am especially happy about the fact that the package will be now usable without an internet connection.