RFC: quadratic to conic wrapper (with LP duals)

``MathProgBase.ConicSolverWrapper(ECOS.ECOSSolver(verbose=false))`` passes the JuMP LP tests. SOC constraints coming up.
To work around a broken corner case of julia's type inference. Otherwise
```
status(wrap::ConicModelWrapper) = status(wrap.m)
```
gets inferred to return ``None``.