Fix issue where findClosestAirport might return the wrong airport if
multiple airports were within the 0.001 criteria.
Added correctionFactor to distance calc as described here:
http://stackoverflow.com/questions/3695224/android-sqlite-getting-nearest-locations-with-latitude-and-longitude
Merge pull request #49 from rasii/fixFindClosestAirport

Fix DatabaseHelper.findClosestAirportID bug