LaTeX printing bug hunt

Separate numbers with \cdot by default. Print True/False as latex mathrm and prevent IPython from printing True/False as latex at all. Add an empty {} argument to \begin{array} constructs.

Fixes the following issues:

Issue 3740: Don't use \times in latex
http://code.google.com/p/sympy/issues/detail?id=3740

Issue 3757: True and False in latex
http://code.google.com/p/sympy/issues/detail?id=3757

Issue 3861: latex(Matrix, mat_str='array') misses first element
http://code.google.com/p/sympy/issues/detail?id=3861