ComplexWarning Bug

[joseJCS0]

When trying to run a data simulation for tutorials an error occurred caused by code In the core.py file (...\site-packages\deepdish\core.py) on line 8 the original code "warnings.simplefilter("ignore", np.ComplexWarning)". Locally fixed when removing the "np.ComplexWarning" new code: "warnings.simplefilter("ignore")"

[jeremymanning]

@joseJCS0 thanks for submitting these issues!! for the issues where you've made local fixes, would you be interested in submitting a pull request?