[SciPy-Dev] PR #195: optimize.root - interface to root finding algorithms

Hi, In pull request #195, I am proposing the addition of a unified interface `optimize.root` for root finding algorithms for multivariate functions, similar to `optimize.minimize` and `optimize.minimize_scalar` (already merged). Available solvers are: - hybr: MINPACK's hybrid Powell algorithm (fsolve) - lm: MINPACK's Levenberg-Marquardt algorithm (leastsq) - and solvers from optimize.nonlin (broyden1, krylov, etc.) See <https://github.com/scipy/scipy/pull/195>. Comments welcome. Thanks, Denis.