[builder] Add an entry for ROS for the PTUPosture sensor

Spotted by Lars Kunze
[bin/morse.in] 2.68 seems ok for Morse!
[actuator] new 3D sound
[sound] enable 3D effect using activate()
[geolandloader] remove Blender 2.4x code
[tools] new terrain creator tool (geotiff/dtm)
[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
[actuator/waypoint] not active if no new goal

fix #416 was interfering other motion actuator.
[camera] fix orientation

Thanks to Lars Kunze for repporting on the mailing list.

ROS conventions suggest a coordinate frame for camera as follows:
(cf. http://www.ros.org/reps/rep-0103.html#coordinate-frame-conventions)

z forward
x right
y down
Add support for 'morse import <path>'

This allows to import pre-existing simulations in MORSE
for later run them with 'morse run' (or 'morse edit').

'path' must be a local path.

Partially fix #396
[doc] Added a 'quickstart' tutorial

It illustrates to use of 'morse create' and friends.

Partially fix #396
Implement a template for sensors

Used when calling 'morse add sensor ...'

Partially fix #396
[doc] Document in more places 'morse create|add'

Related to issue #396
Removed non-standard ROS serialization for KUKA joints

Originally introduced in #301. The normal way to add custom
serialization is now with 'add_stream'. Cf
http://www.openrobots.org/morse/doc/latest/user/builder.html#middleware-configuration
[unittest] Add a test for 2 Segway RMP400

Exhibit a wheel parenting bug due to Blender renaming wheels.
Spoted by Caleb Voss.
[doc] Updated RELEASE_NOTES/what's new
Revert "Removed non-standard ROS serialization for KUKA joints"

This reverts commit c1ae95a1b4a7cf40ffe0711e7226960c127d4f64.

This encoding is in fact 'relatively standard', as it is part of the
ros-orocos interface, and brics-actuator interface.
[doc] add sound to generate_doc