added webservice methods to retrieve performance data
merging with master
merged with master
updated to use QUERY_PARAMS.getlist
added stuff for performance_artifact endpoint
fixed SUM to test for null, rather than 0 rows
fixed some things jeads talked about
fixed some things resulting from jeads fixes. everything should be working now
merging with master
added explicit host to sql selects
fixed a line that had tabs
Merge pull request #176 from mozilla/performance-endpoints

added webservice methods to retrieve performance data