Fix #15 - installing from pip and easy_install (Take 2)

[ccpost]

• Ensure that the build_ext task is called before build_py to
  generate SWIG .py files before the Python copy step happens and we
  miss packaging and installing the generated files.
• Add Makefile target test_install for testing multiple build and
  install methods on the active Python installation.

This is much cleaner; not sure why it didn't occur to me last night. I think this should work with any install method entry point into setuptools because it's explicitly hooking into build_py, which should always be called.

The new Makefile target isn't the cleanest thing ever. I just wanted an automated way to test the whole clean installation loop into my local Python install.

[coveralls]

Coverage remained the same at 18.295% when pulling 55680b2 on ccpost:fix/pip-install-take-two into defecae on LudovicRousseau:master.

[coveralls]

Coverage remained the same at 18.295% when pulling e09bc6f on ccpost:fix/pip-install-take-two into defecae on LudovicRousseau:master.

[LudovicRousseau]

How is the test_install target supposed to be used?
Is it only for tests on your side or should I really add it in the project?

[ccpost]

Up to you whether you want to include it or not. I don't imagine anyone would ever want to run it unless they were actively debugging this issue, since it does a real install into whatever Python you have active. I was just rolling up the steps I was initially doing manually to run through the different installation cases automatically.

Should I remove?

[LudovicRousseau]

yes, please. Remove it.

[coveralls]

Coverage remained the same at 18.295% when pulling 0f59ade on ccpost:fix/pip-install-take-two into defecae on LudovicRousseau:master.