Task: plugin quadrotor for Gazebo requires full refactor

[varhub]

I think that a full refactor of quadrotor plugin is mandatory:

At least for:

• Separate code logic from Ice interfaces
• Remove code from headers
• Improve namespaces

An eventually for:

• Reduce thread requirements to one
• Split control from sensoring if possible

[Iter I]

[varhub]

Mission complete.

Requires some extra job.

• Implement dual Pose3D (real and altitude) with Ice facets
• Solve Z drift
• implement teleport (setPose)
• Use EasyIce to allow run gazebo from any directory

[varhub]

This task include fixing: #216 #217 #218

• plugin quadrotor for Gazebo: memory leak? #216 fixed since camera frame is always taken from reference and Ice is correctly closed
• plugin quadrotor for Gazebo: vertical bias #217 reproduced but with reverse sign
• plugin quadrotor for Gazebo: take off error #218 fixed by use novel control to determine that error must be outside

Update: #216 was characterized here: #104 (#104 is also fixed)

[varhub]

Sorting ToDo:

1. Use EasyIce
2. Implement dual Pose3D
   • The ultrasonic altimeter of ardrone plugin doesn't works #223
3. Implement teleport
4. Solve Z drift plugin quadrotor for Gazebo: vertical bias #217
5. Customizable parameters (sdf)
   1. fly altitude (take off)
   2. take off/landing speed

[Iter II]