Remove all external dependencies

[apankrat]

Hi Joseph,

I don't know if you might be interested in this patch, but just in case here it is. If not, then not. Just close the PR and no offense will be taken.

It removes external dependencies for MathJax and JQuery and strips the Google Analytics link. It also moves all secondary files into extras subfolder, just to make things a bit tidier Aside from this, there are no other changes.

Cheers,
Alex

[apankrat]

Bah, forgot to say - Thanks a bunch for the code. Wonderful stuff, very clean.

I tweaked it a bit to my needs - reduced font sizes, tweaked keyboard shortcuts, extended markdown syntax a bit and hooked it up to simple server-based sync. Basically it now allows creating an offline-first webpage that can be edited at will -- makes for an excellent note taking app.