round

[jverzani]

This came up in https://discourse.julialang.org/t/how-to-round-whole-matrix-like-numpy-round/84897

What should be the proper semantics of round for Sym objects:

• sympy.round() fails on symbolic objects (seems excessive, but what should the result of round(x) be? Could be a delayed call or just x
• sympy.round() only supports digits, not sigdigits or base, as Base.round
• sympy.round() does not support rounding modes