3722: more advanced re/im support

>>> from sympy.abc import *
>>> from sympy import *
>>> solve([abs(x) - 2, arg(x) - pi],x)
[{re(x): -2, x: -2, im(x): 0}, {re(x): 2, x: 2, im(x): 0}]
>>> solve([re(x) - 1, im(x) - 2], x)
[{re(x): 1, x: 1 + 2*I, im(x): 2}]