setup: Use pip.req.parse_requirements to read requirements

This approach (while controversial - see [1][2][3]) has the advantage of
supporting all formats (e.g vcs)

[1] https://caremad.io/2013/07/setup-vs-requirement/
[2] http://stackoverflow.com/questions/14399534/how-can-i-reference-requirements-txt-for-the-install-requires-kwarg-in-setuptool#16624700
[3] https://www.reddit.com/r/Python/comments/3uzl2a/setuppy_requirementstxt_or_a_combination/

Author: jcfr

setup.py

@@ -2,8 +2,15 @@
 
 import versioneer
 
+from pip.req import parse_requirements
 from skbuild import setup
 
+
+def _parse_requirements(filename):
+    return [str(ir.req) for ir in parse_requirements(filename, session=False)]
+
+dev_requirements = _parse_requirements('requirements-dev.txt')
+
 setup(
     name='cmake',
 
@@ -54,6 +61,6 @@
 
     keywords='CMake build c++ fortran cross-platform cross-compilation',
 
-    install_requires=[
-    ]
+    install_requires=[],
+    tests_require=dev_requirements,
     )