DEPS: drop numpy < 1.9

[jreback]

this would provide some code cleanup possibilities.

• use np.full (see COMPAT: np.full not available in all versions, xref #16773 #17000 for example)

[jreback]

cc @shoyer
cc @njsmith
cc @charris
cc @wesm

[tacaswell]

That seems a bit aggressive, mpl supports back to 1.7.1.

[wesm]

I don't have a problem with this. Upgrading NumPy is not as much of a hardship nowadays as it used to be.

[njsmith]

I think from the numpy perspective this can only be a good thing. We'd much rather people be using the latest and greatest rather than carrying around compatibility hacks.

[bashtage]

I'm not sure there are lots of gains from dropping NumPy 1.9. 1.7 and 1.8 probably do have some meaningful workarounds.

[jreback]

revising to 1.9, which should give us good gains from 1.7/1.8 compat, but still allow mpl 1.4.3 support.