[release_notes] add a row on 3D sound actuator
[release_notes] add terrain tools notes
[ci] travis: exit on error

use `bash -e` to exit the script on error
Added charging behavior.

The battery sensor now senses charging zones. A charing zone is added as property to any object in the world. If the sensor is in a certain range of this object, the battery gets charged.
Test for topic_suffix argument. Default: '/image'
Added flag that indicates whether the battery is charging. Changed ROS msg from Float32 to BatteryState (scitos_msgs). Currently only lifePercent and charging are supported.
Merge branch 'master' of https://github.com/strands-project/morse
Merge branch 'master' of https://github.com/morse-simulator/morse
Added battery state sensor. Reverted orignial battery sensor.
Merge pull request #2 from kunzel/master

That looks good now. Added battery charging and battery state ROS interface