Initial messing around.

Latex tab completion will have to be done outside the normal
completer logic as the completer line splitting logic uses
\\ as a special character to split lines on. I probably want
to put the latex completions first and it if finds any matches,
don't do any other completion logic. The only issue is that might
short circuit dir/path matching on windows. Hmmm.
Adding autogenerated latex_symbols.py.
Adding regexp for unicode identifers to CM mode.
Initial implementation of latex->unicode completer.
Cleaning up and only doing latex completion for python 3.
Adding partial latex completions.
Adding tests and limiting CM mode to python 3.
Adding latex_symbols.ipynb.
Adding script to generate latex_symbols.py.
Updating gen_latex_symbols.py
Fix typo
Simplify test_ident using str.isidentifier()

I have checked that this gives the same results as the previous method.
Remove leftover debugging
Merge pull request #19 from takluyver/latex-complete-fixes

Latex completion fixes
Add docstring for latex_matches method
Merge pull request #20 from takluyver/latex-complete-docstring

Add docstring for latex_matches method
Merge pull request #6380 from ellisonbg/latex-complete

Adds Julia-style latex->unicode tab completion