reworked the schema validators so that we drop measurement nodes that
are missing lat or lon
added better comments to changes in the submit schema validator
relaxed the check for empty wifi and cell sets so that just those records are dropped from the batch of records
Fixed a bunch of tests which incorrectly flagged errors that shouldn't be happening
changed the test_error test case to use an invalid JSON blob to force a 400 server error
deleted a commented piece of code
changed the out of range lat/lon from -1 to -255
moved the check for WifiMeasure records in the skip missing lat/lon
testcase
Merge pull request #174 from crankycoder/features/170-allow-empty-records

Features/170