Move paid task summary as separate rows to the total summary

Avoid selecting tasks from DB when getting the total summary. Generate paid task
summary in JS instead (using task list already received).
Fix #300
Fix flot.js chart rendering

Group data by date in local time, but provide timestamps in UTC to flot.js
Linked with 535a95b
Improve translated/reviewed word counting algorithm

If we edited an existing translation we counted this action as review
always. If the similarity is below threshold we treat such editing
as translation now.
Round all translated word count to 2 digits, ceil all sums