Update release tool to always produce zip file.

tools/build_release

@@ -1,42 +1,42 b''
 #!/usr/bin/env python
 """IPython release build script.
 """
 from toollib import *
 
 # Get main ipython dir, this will raise if it doesn't pass some checks
 ipdir = get_ipdir()
 cd(ipdir)
 
 # Load release info
 execfile(pjoin('IPython','core','release.py'))
 
 # Check that everything compiles
 compile_tree()
 
 # Cleanup
 for d in ['build','dist',pjoin('docs','build'),pjoin('docs','dist')]:
     if os.path.isdir(d):
         remove_tree(d)
 
 # Build source and binary distros
-c('./setup.py sdist --formats=gztar')
+c('./setup.py sdist --formats=gztar,zip')
 
 # Build version-specific RPMs, where we must use the --python option to ensure
 # that the resulting RPM is really built with the requested python version (so
 # things go to lib/python2.X/...)
 c("python2.5 ./setup.py bdist_rpm --binary-only --release=py25 "
   "--python=/usr/bin/python2.5")
 c("python2.6 ./setup.py bdist_rpm --binary-only --release=py26 "
   "--python=/usr/bin/python2.6")
 
 # Build eggs
 c('python2.5 ./setupegg.py bdist_egg')
 c('python2.6 ./setupegg.py bdist_egg')
 
 # Call the windows build separately, so that the extra Windows scripts don't
 # get pulled into Unix builds (setup.py has code which checks for
 # bdist_wininst)
 c("python setup.py bdist_wininst --install-script=ipython_win_post_install.py")
 
 # Change name so retarded Vista runs the installer correctly
 c("rename 's/linux-i686/win32-setup/' dist/*.exe")