More consistent script handling.

 - Add pip installed script for submit.py (pulsar-submit).
 - Rename script for run.py to pulsar-run.

setup.py

@@ -95,7 +95,8 @@ setup(
         pulsar-drmaa-launch=pulsar.scripts.drmaa_launch:main
         pulsar-drmaa-kill=pulsar.scripts.drmaa_kill:main
         pulsar-chown-working-directory=pulsar.scripts.chown_working_directory:main
-        pulsar-submit=pulsar.scripts.run:main
+        pulsar-submit=pulsar.scripts.submit:main
+        pulsar-run=pulsar.scripts.run:main
     ''',
     scripts=scripts,
     package_data={'pulsar': [