Split requirements.txt in runtime & development

Also added secondary requirements to the files.

requirements-dev.txt

@@ -0,0 +1,16 @@
+# Development requirements
+tox==2.3.1
+wheel==0.29.0
+coverage==4.0.3
+pytest==3.0.1
+pytest-xdist==1.14
+pytest-cov==2.3.1
+responses==0.5.1
+
+# Secondary development requirements
+apipkg==1.4
+cookies==2.2.1
+execnet==1.4.1
+pluggy==0.3.1
+py==1.4.32
+virtualenv==15.1.0

requirements.txt

@@ -2,11 +2,13 @@
 pyOpenSSL==0.15.1
 requests==2.9.1
 
-# Development requirements
-tox==2.3.1
-wheel==0.29.0
-coverage==4.0.3
-pytest==3.0.1
-pytest-xdist==1.14
-pytest-cov==2.3.1
-responses==0.5.1
+# Secondary requirements
+appdirs==1.4.2
+cffi==1.9.1
+cryptography==1.7.2
+idna==2.4
+pyasn1==0.2.3
+packaging==16.8
+pycparser==2.17
+pyparsing==2.1.10
+six==1.10.0