use a console_script instead of a script for Windows compat

NEWS

@@ -31,6 +31,8 @@
   environment variable was not set.
 * Fixed removal of albums (beet remove -a): previously, the album
   record would stay around although the items were deleted.
+* The setup script now makes a beet.exe startup stub on Windows; 
+  Windows users can now just type "beet" at the prompt to run beets.
 
 1.0b3
 -----

setup.py

@@ -40,7 +40,11 @@ setup(name='beets',
           'beetsplug.bpd',
       ],
       namespace_packages=['beetsplug'],
-      scripts=['beet'],
+      entry_points={
+          'console_scripts': [
+              'beet = beets.ui:main',
+          ],
+      },
 
       install_requires=[
           'mutagen',