Centering equation in markdown and code cells.
Added new structure (input prompt and inner cell) to markdown cells.
Restructuration of null.tpl and addition of inner_cell classes.
Rename of input groups and use of self.block for e_in_prompt.
Deleting html clases for raw and unknown type cells.
Simplification of the logic.
Coming back raw cell to null template.
null.tplx regenerated.
Make the name of empty_in_prompt more explicit.
Fixed mathjax macro to be synced with the mathjax config in the live notebook.
Make the null templates compatible with the last Thomas's commit.
Deal with ansi escape codes when nbconverting to latex

Correctly deals with "reset" codes and short codes.  Interprets blinking
style as bold.
Added widget output area
Add widget subarea style
Added dependencies to page.html template and added widget.js to notebook.html
Added widget.js
Added widget.py
Added widjet.js
Other commit actually added notebook.js changes
Fixed widget.js and notebook.js so IPython.notebook.widget_manager is created.
Fixing infinite recursion.