Fixing Fail on checking "in None"

tables without colspec might lead to a little unhappy error. `latex_mod.py`'s `depart_table()` checks if some strings are in the `colspec`, but if `colspec` is None, the whole program will fail. Therefore I think it might be a good idea to replace the instances in which `colspec` is empty/None/False with an empty string. Checking for something `in` empty strings is okay.

The rest of the changes just remove some whitespace.