Undefined variables in function calc_theta_delta_bounds

[rb004f]

In function calc_theta_delta_bounds, when the function drops into line 76, it references undefined variables amin and amax and throws an UndefVarError

[ccoffrin]

Good catch. I have merged a test and a fix, do you need a new release tagged right away?

On a side note, this example made me realize there is a bunch of "conductor" based features that could probably be removed from PM now that PMD is basically a stand alone package. Do you see a reason to keep supporting "conductors" in PM?

CC @pseudocubic

[rb004f]

No, I don't need a new release right away. And yes, it seems like we are migrating away from having multi conductor support in PowerModels and have it all in PMD.