glim_ros1 draws 100% CPU on idle to to busy spinning without wait

[skohlbr]

Describe the bug When starting the glim_rosnode.launch file and not feeding it any data (so it just sits there idling around), it the process consumes a full CPU core. This is due to ros::spinOnce() getting called without a wait/sleep inbetween.

To Reproduce

1. Run roslaunch glim_ros glim_rosnode.launch
2. Observe CPU consumption using top or another tool. It will show the GLIM process at 100%

Expected behavior When the process is idling it should consume low ( < ~5%) CPU.

Environment (please complete the following information):

• Ubuntu 18.04/melodic/no CUDA (yes, I had to do some mods to make things compile, but this issue should be unaffected by that)

[skohlbr]

(Would be) fixed by https://github.com/koide3/glim_ros1/pull/16