Support multiple fields in --group-by

This allows --group-by to take a comma-separated list of field names,
and processes the field list before passing it to the SQLProcessor. When
displaying the results, it displays as two separate fields.
Merge pull request #29 from jreese/groupby

Support multiple fields in --group-by
bump version to 0.0.2
Use relative imports. Fixes #33
Merge pull request #37 from jleclanche/fix/33

Use relative imports. Fixes #33
Nginx variables can contain uppercase letters 

e.g. jssessionid=$cookie_JSESSIONID
Merge pull request #44 from amuraru/patch-1

Nginx variables can contain uppercase letters
Merged with upstream