AJAX evaluation, plot planning, updated style

Changes:

- Cards are evaluated with AJAX now
  - Numerical cards allow "more digits" (http://sympy-gamma-li.appspot.com/input/?i=242/33)
- Plots can be dragged/zoomed (will fetch data from server as necessary for panning) (http://sympy-gamma-li.appspot.com/input/?i=sin%28x%29+%2B+cos%28x%29)
- Android compatibility
- Style overhaul

If possible, I'd like the functionality from https://github.com/sympy/sympy/pull/1669 to use for LaTeXifying input with an AST and for implicit application/multiplication. (I see the latest merge failed, but that code is related to matrices?)

Demo: http://sympy-gamma-li.appspot.com/

![Screenshot from 2013-01-29 17:26:41](https://f.cloud.github.com/assets/327919/109268/e0d4185c-6a73-11e2-9571-ca384a746134.png)
![Screenshot from 2013-01-29 17:27:06](https://f.cloud.github.com/assets/327919/109269/e0dbc746-6a73-11e2-9f30-26643a9e4529.png)
![Screenshot from 2013-01-29 17:27:34](https://f.cloud.github.com/assets/327919/109270/e0dce28e-6a73-11e2-9b14-73c59ca15176.png)