Maybe a step to make HaTeX really useful for math-heavy applications

Hello Daniel,

I've been thinking about switching to HaTeX for quite a while. Being a physics student, I need to write lots of math and I'm increasingly dissatisfied with LaTeX' macro architecture. HaTeX appears to be a nice clean compact binding layer, however I can't seem to find it sufficiently abstract to be a real improvement over plain LaTeX. That's why I started [some experiments](https://github.com/leftaroundabout/Symbolic-math-HaTeX), but even there I initially found myself rather writing raw LaTeX math than using the `AMSMath` module.

Perhaps I just don't get this package right, but it seems to me that it's being kept just a bit to slim. I thought I'd just see what happens if I add the various math bracket delimiting constructs to the `LaTeX` datatype, and here we are. Not sure if you like it, perhaps I should rather  do those things in my own project.

On the other hand, maybe you would actually like to get some more agressive math support into HaTeX? I don't know.

Regards, and otherwise Merry Christmas etc.,
Justus