Pegs version in setup.py then imports that in the module __init__ code.

If I try to install zygote from PyPI using version 0.5.2, it doesn't work because setup.py is defining the package using itself; this will only work if there's another version lying around. I get the following in a fresh virtualenv:
```
$ pip install zygote -v
Downloading/unpacking zygote
  Using version 0.5.2 (newest of versions: 0.5.2, 0.5, 0.4, 0.3)
  Downloading zygote-0.5.2.tar.gz
  Downloading from URL https://pypi.python.org/packages/source/z/zygote/zygote-0.5.2.tar.gz#md5=a976a42f3e843a6a0553e617005d4ac8 (from https://pypi.python.org/simple/zygote/)
  Running setup.py egg_info for package zygote
    Traceback (most recent call last):
      File "<string>", line 16, in <module>
      File "/nail/home/dselassi/zygote/TEST/build/zygote/setup.py", line 4, in <module>
        from zygote import version
    ImportError: No module named zygote
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):

  File "<string>", line 16, in <module>

  File "/nail/home/dselassi/zygote/TEST/build/zygote/setup.py", line 4, in <module>

    from zygote import version

ImportError: No module named zygote

----------------------------------------
```

I followed the advice of http://stackoverflow.com/questions/2058802/how-can-i-get-the-version-defined-in-setup-py-setuptools-in-my-package . If I tell `pip` to look at a local sdist I just made of this new version 0.5.3, it works:
```
~/zygote(version-in-setup)$ pip install zygote -f ./dist/ -v
Downloading/unpacking zygote
  Local files found: /nail/home/dselassi/zygote/dist/zygote-0.5.3.tar.gz
  Using version 0.5.3 (newest of versions: 0.5.3, 0.5.2, 0.5, 0.4, 0.3)
  Running setup.py egg_info for package zygote
    running egg_info
    creating pip-egg-info/zygote.egg-info
    writing requirements to pip-egg-info/zygote.egg-info/requires.txt
    writing pip-egg-info/zygote.egg-info/PKG-INFO
    writing top-level names to pip-egg-info/zygote.egg-info/top_level.txt
    writing dependency_links to pip-egg-info/zygote.egg-info/dependency_links.txt
    writing entry points to pip-egg-info/zygote.egg-info/entry_points.txt
    writing manifest file 'pip-egg-info/zygote.egg-info/SOURCES.txt'
    warning: manifest_maker: standard file '-c' not found
    reading manifest file 'pip-egg-info/zygote.egg-info/SOURCES.txt'
    writing manifest file 'pip-egg-info/zygote.egg-info/SOURCES.txt'
Requirement already satisfied (use --upgrade to upgrade): setuptools in ./TEST/lib/python2.6/site-packages (from zygote)
Downloading/unpacking tornado (from zygote)
...
```