Only test numpy with py27 and py35.

Travis was not successfully installing numpy with python<=2.6,
python<=3.3, or PyPy.  I decided that it didn't make sense to use numpy
for all the tests, so instead I made new testing environments
specifically for numpy.

.travis.yml

@@ -16,13 +16,16 @@ env:
     - TOXENV=py33
     - TOXENV=py34
     - TOXENV=py35
+    - TOXENV=py36
     - TOXENV=pypy
     - TOXENV=py27-pexpect
     - TOXENV=py27-xdist
     - TOXENV=py27-trial
+    - TOXENV=py27-numpy
     - TOXENV=py35-pexpect
     - TOXENV=py35-xdist
     - TOXENV=py35-trial
+    - TOXENV=py35-numpy
     - TOXENV=py27-nobyte
     - TOXENV=doctesting
     - TOXENV=freeze

appveyor.yml

@@ -20,9 +20,11 @@ environment:
   - TOXENV: "py27-pexpect"
   - TOXENV: "py27-xdist"
   - TOXENV: "py27-trial"
+  - TOXENV: "py27-numpy"
   - TOXENV: "py35-pexpect"
   - TOXENV: "py35-xdist"
   - TOXENV: "py35-trial"
+  - TOXENV: "py35-numpy"
   - TOXENV: "py27-nobyte"
   - TOXENV: "doctesting"
   - TOXENV: "freeze"

tox.ini

@@ -12,7 +12,7 @@ envlist=
      py36
      py37
      pypy
-     {py27,py35}-{pexpect,xdist,trial}
+     {py27,py35}-{pexpect,xdist,trial,numpy}
      py27-nobyte
      doctesting
      freeze
@@ -26,7 +26,6 @@ deps=
     nose
     mock
     requests
-    numpy
 
 [testenv:py26]
 commands= pytest --lsof -rfsxX {posargs:testing}
@@ -111,6 +110,16 @@ deps={[testenv:py27-trial]deps}
 commands=
   pytest -ra {posargs:testing/test_unittest.py}
 
+[testenv:py27-numpy]
+deps=numpy
+commands=
+  pytest -rfsxX {posargs:testing/python/approx.py}
+
+[testenv:py35-numpy]
+deps=numpy
+commands=
+  pytest -rfsxX {posargs:testing/python/approx.py}
+
 [testenv:docs]
 skipsdist=True
 usedevelop=True