Streamline python package structure

The adsbibdesk.py at the root of the repo is now the adsbibdesk.py for
the python package itself. No more needing to 'build' the python
package. This was left-over from the days of injecting AppleScript into
Python code.

Now a user can just clone the repo and `python setup.py install` right
away!

closes #40
python setup.py service to run Service build

This setuptools command in setup.py runs the app build script, which
used to be in a separate build.py. Thus to build the automator action,
just run

python setup.py service

Also Add logging feedback to build.py: It's reassuring to know that
something is *actually* happening there.

As a result of doing this, it seems that the App is not getting updated;
only the service. I need to look at this.
Make VERSION in adsbibdesk.py authoritative

setup.py will scrape VERSION from adsbibdesk.py to get the package
version string. This VERSION is also used by optparse.

Basically, there's only one place to bump the version string now.