Remove now-redundant pytest settings from setup.cfg.

The markers are now in conftest.py, and the doctest settings appear to
be unnecessary.

Author: QuLogic

setup.cfg

@@ -11,12 +11,6 @@ exclude = \
     versioneer.py
 
 
-[tool:pytest]
-markers =
-    natural_earth: mark tests that use Natural Earth data, and the network, if not cached.
-    network: mark tests that use the network.
-doctest_optionflags = ELLIPSIS NORMALIZE_WHITESPACE
-
 [versioneer]
 # See the docstring in versioneer.py for instructions. Note that you must
 # re-run 'versioneer.py setup' after changing this section, and commit the