solrjmeter should be made python 3.x compatible

[vvolkman]

My initial runs show nothing which will prevent Python 3.x from being used with the notable exceptions

1. Put parenthesis around all print() statements
2. Use Exception syntax that works in both Python 2 and python 3, notably
   except Exception as e:
   instead of
   except Exception, e:

[romanchyla]

Thank you for the report, i've just fixed it and pushed python3 - not having too much time to test it myself, would you mind trying it?