Updated setup.py to use entry_points['console_scripts'] instead of scripts.

This makes a "mkdocs" command on Windows/OSX/Linux without any platform-specific code in setup.py.

I think this is the preferred way to install a Python command with setuptools.

It is, at least, the method used by:

* [flake8](8ee94d1eee/setup.py)
* [coverage.py](ca875e7390/setup.py)
* [Fabric](https://github.com/fabric/fabric/blob/master/setup.py)
* Many others

In the past, I had to change imports willy-nilly or add
"from __future__ import absolute_imports" to a bunch of files.
This is because I was renaming "mkdocs" to "mkdocs.py" instead of "main.py",
and the module-vs-script name clash was confusing imports from other files.

mkdocs/main.py

@@ -39,7 +39,16 @@ def main(cmd, args, options=None):
     else:
         print('mkdocs [help|new|build|serve|gh-deploy] {options}')
 
-if __name__ == '__main__':
+def run_main():
+    """
+    Invokes main() with the contents of sys.argv
+
+    This is a separate function so it can be invoked
+    by a setuptools console_script.
+    """
     cmd = sys.argv[1] if len(sys.argv) >= 2 else None
     opts = [arg_to_option(arg) for arg in sys.argv[2:] if arg.startswith('--')]
     main(cmd, args=sys.argv[2:], options=dict(opts))
+
+if __name__ == '__main__':
+    run_main()

setup.py

@@ -80,7 +80,11 @@ setup(
     packages=get_packages(package),
     package_data=get_package_data(package),
     install_requires=install_requires,
-    scripts=['mkdocs/mkdocs'],
+    entry_points={
+        'console_scripts': [
+            'mkdocs = mkdocs.main:run_main',
+            ],
+        },
     classifiers=[
         'Development Status :: 5 - Production/Stable',
         'Environment :: Web Environment',