Stats processing: Recognize Firefox Tablet correctly

Review: http://codereview.adblockplus.org/6205888910065664
Fixed logprocessor.parse_record unit tests, mirror name is set elsewhere now

Review: http://codereview.adblockplus.org/5050692091772928/
Stats processing: Fix handling of boolean keys

Review: http://codereview.adblockplus.org/6176591998615552
Stats processing: Fixed last day of month being below the fold

http://codereview.adblockplus.org/5662084981325824