Parameter gui_publish_rate is never used

[corot]

However, it is documented in the wiki and present in example launch files and dynamic configuration.

Conversely, skip parameters are used but not documented on wiki nor in example launch files:

• do_beamskip
• beam_skip_distance
• beam_skip_threshold
• beam_skip_error_threshold_

I would also remove the trailing '' on beam_skip_error_threshold

[mikeferguson]

the undocumented parameters were added in 3dbecae, not sure what happened to gui_publish_rate....