When table.el tables are exported to latex, stuff like the dollar sign
is all escaped, so that you cannot make a table of latex equations.

This diff just adds a variable that works adding a variable that let's
the user control what is escaped and what is not.  Since backslashes
cannot be escaped the same way as charecters like '$', instead of making
2 vairbales( one for backslash and other for chars), I just added one
cons cell.

Instead of using string, I think using regexp better choice as it allows
for more complex escaping, such as turning mentions of "LaTeX" to
"\Latex".

Overall, this fixes the problem of being able to have column
wrapped paragraphs which include tex equations in some org exports.