Updated pre-install to not use __FILE__ which does not respect symlinks
Added eachMeasurement method for iteration
Added eachReading and eachMeasurement methods for iteration
Changed getRealtimeData to fetch for all measurements at once, instead of each separately
Added tests for eachReading and eachMeasurement iteration methods
Merge pull request #68 from jmfee-usgs/realtime-data-optimization

Realtime data optimization
Merge pull request #67 from jmfee-usgs/pre-install-update

Updated pre-install to not use __FILE__ which does not respect symlinks