Try to install less stuff: cryptography doesn't build on windows

ci-requirements.txt

@@ -12,8 +12,10 @@ greenlet>=0.4.13 ; platform_python_implementation == "CPython"
 pylint>=1.8.0
 # pyyaml is included here and doesn't install on travis with 3.7a3
 prospector[with_pyroma] ; python_version < '3.7'
-coverage>=4.0
-coveralls>=1.0
+# We don't run coverage on Windows, and pypy can't build it there
+# anyway (coveralls -> cryptopgraphy -> openssl)
+coverage>=4.0 ; sys_platform != 'win32'
+coveralls>=1.0 ; sys_platform != 'win32'
 # See version requirements in setup.py
 cffi >= 1.11.5 ; platform_python_implementation == "CPython"
 futures
@@ -26,12 +28,3 @@ perf
 # Events
 zope.event
 zope.interface
-
-# Tests
-requests
-# For viewing README.rst (restview --long-description),
-# CONTRIBUTING.rst, etc.
-# https://github.com/mgedmin/restview
-restview
-
--r rtd-requirements.txt

dev-requirements.txt

 -r ci-requirements.txt
+-r rtd-requirements.txt
 -e .