[RFC] Do not use ^ as representation for exponentiation

[Jose E. Marchesi]

Hello.

I propose to stop supporting `^' as an alternative represetnation of
"**" and UP.

Reasons:

1. A symbolic representation, plus a bold word representation for a
   given operator is more than enough IMO.

2. This way the worthy character `^' gets free for other potential uses.

Objections?