PyRoaringBitMap: Installation using wheel is broken

Hi,

We plan to use this library at Datadog (https://github.com/DataDog) and we use wheels to install the Python libs. While trying to install pyroaring, I found out that it doesn’t work when using wheel as the roaring.hh header file isn’t included in the wheel:

qf~$ sudo pip wheel pyroaring
qf~$ unzip pyroaring-0.1.5-cp27-cp27mu-linux_x86_64.whl
Archive:  pyroaring-0.1.5-cp27-cp27mu-linux_x86_64.whl
  inflating: pyroaring.so
  inflating: pyroaring-0.1.5.dist-info/DESCRIPTION.rst
  inflating: pyroaring-0.1.5.dist-info/metadata.json
  inflating: pyroaring-0.1.5.dist-info/top_level.txt
  inflating: pyroaring-0.1.5.dist-info/WHEEL
  inflating: pyroaring-0.1.5.dist-info/METADATA
  inflating: pyroaring-0.1.5.dist-info/RECORD

The fix I found is to explicitely set the required headers in setup(): https://github.com/DataDog/PyRoaringBitMap/commit/ed652576556509141d31077a3e4967503110533a. Can I submit this fix or could you take look when you get a chance?

Thanks, Quentin