ZArith v1.10

• Improvement #66: added some mpz functions (divisible, congruent, jacobi, legendre, krobecker, remove, fac, primorial, bin, fib, lucnum)
• Improvement #65: Q.of_string now handles decimal point and scientific notation [Ghiles Ziat]
• Fix #60: Z.root now raises an exception for invalid arguments
• Fix #62: raise division by 0 for 0-modulo in powm
• Fix #59: improved abs for negative arguments
• Fix #58: gcd, lcm, gcdext now behave as gmp for negative arguments
• Fix #57: clean compile with sage strings [hugo]