Mahler measure of integer polynomials

The main purpose of this file is to prove Northcott's Theorem for the Mahler measure.

Main results

• Polynomial.finite_mahlerMeasure_le: Northcott's Theorem: the set of integer polynomials of degree at most n and Mahler measure at most B is finite.
• Polynomial.card_mahlerMeasure_le_prod: an upper bound on the number of integer polynomials of degree at most n and Mahler measure at most B.