MAINT: Fix for upcoming bump in scipy

[sjsrey]

This adds a fix for breakage that will occur when moving from scipy 1.2.1 to 1.3.0.

pysal-meta has encountered these breaks downstream.

It also drops 3.5 support following the decision to do so in the meta-package.

[jGaboardi]

an accidental push caused #22 and (I think) is why 30efd6c is failing.

[jGaboardi]

@weikang9009 The travis test is failing because I made a push from a testing branch (#22, see travis error below) which had been deleted. The only changes from 28c79b to 30efd6c
are several addition spaces, nothing substantive at all. This is OK to merge (in my opinion)

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$ git fetch origin +refs/pull/22/merge:
fatal: couldn't find remote ref refs/pull/22/merge
The command "eval git fetch origin +refs/pull/22/merge: " failed. Retrying, 2 of 3.
fatal: couldn't find remote ref refs/pull/22/merge
The command "eval git fetch origin +refs/pull/22/merge: " failed. Retrying, 3 of 3.
fatal: couldn't find remote ref refs/pull/22/merge
The command "eval git fetch origin +refs/pull/22/merge: " failed 3 times.
The command "git fetch origin +refs/pull/22/merge:" failed and exited with 128 during .
Your build has been stopped.