Don't append the global plan

[rokusottervanger]

We append the global plan with the carrot distance here:

path_tracking_pid/src/controller.cpp

Lines 190 to 196 in 61c6cc8

	if (!config_.track_base_link) {
	// Add carrot length to plan using goal pose (we assume the last pose contains correct angle)
	tf2::Transform carrotTF(
	tf2::Matrix3x3(1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0),
	tf2::Vector3(config_.l, 0.0, 0.0));
	global_plan_tf_.push_back(global_plan_tf_.back() * carrotTF);
	}

But there are a few problems with this:

• this distance may change at runtime (dynamic reconfigure), and this is not reflected in the global plan,
• the last pose may not be in the direction of the end of the plan, making the direction in which we append the plan rather arbitrary,