Fix bug with temps overriding temps

There were some bugs in segment util surrounding temps overriding temps.  This change introduces a unit tests to help cover those cases and the fix.

There are a lot of changes to the test fixtures because there were events in there with duplicate ids and the system no likee duplicate ids.
Make better test for the smooshing of values

Fix bugs found by new good test.
move munge_json.py script from blip to tideline
Merge pull request #87 from tidepool-org/cheddar/fix-temp-over-temp

Fix bug with temps overriding temps