added equality checks to sensor-data classes
more robust sensor reader [fixed some issues]
added support for gps
added support for compass
added sensor-data-writer
added test-cases
minor changes
added corresponding test-cases
switched to newer version of tinyxml due to some issues
adjusted affected code-parts accordingly
for better re-use, moved ceiling-calculation to a new class
some minor fixes
new helper methods
worked on wifi-opt
