Merge branch 'eara' into develop
Fixed bug in the OMNeTTimer

There was a problem with restarting existing timers
OMNeTARA does now use the layer2 acks for determining if a link fails.

WARNING: failure handling is not implemented completely now
parameters of the OMNeTBattery are now available in the GUI
Merge branch 'eara' of github.com:des-testbed/Ara-Sim into eara
added battery handling in class OMNeTARA
small changes to the battery notification code