Add preliminary support for UGE (an open source fork of SGE)

SGE's parallel environment specification is space-delimited and UGE is comma delimited.
This handles fix handles both. Other than that it seems to work fine.

Thanks to Andrew Oler for spotting this issue, figuring out what wrong, suggesting
the fix and testing the fix.

cluster_helper/cluster.py

@@ -16,6 +16,7 @@
 import shutil
 import subprocess
 import time
+import re
 from distutils.version import LooseVersion
 import sys
 
@@ -402,8 +403,7 @@ def _queue_can_access_pe(pe_name, queue):
         queue_config = _parseSGEConf(subprocess.check_output(["qconf", "-sq", queue]))
     except:
         return False
-    for test_pe_name in queue_config["pe_list"].split():
-        test_pe_name = test_pe_name.split(",")[0].strip()
+    for test_pe_name in re.split('\W+|,', queue_config["pe_list"]):
         if test_pe_name == pe_name:
             return True
     return False