Lock ocean current calculation function

[woensug-choi]

I think it's that TransientCurrentPlugin::UpdateDatabase is modifying the database (EDIT: and other vectors) in one thread while TransientCurrentPlugin::CalculateOceanCurrent is reading it another.

Field-Robotics-Lab/glider_hybrid_whoi#64

This PR tries to lock and unlock the function.

[daewok]

TransientCurrentPlugin::UpdateDatabase needs to be locked as well.

[woensug-choi]

Leaving a note of your test results,

Then I locked TransientCurrentPlugin::UpdateDatabase as well. It's been running for 6 hours (sim time)/11 minutes (real time) now without an issue.

And about the branch organization,

Most of what we nees would be in #180. It would not include intlatlon, gpaviewer and stuff. So I am trying to keep the bathymetry_plugin_whoi branch at my fork.
the branch will not be in upatream dave and will not be merges into master. Dave team has decided not to include bathymetry files in the repo but make it downloadable reading the tutorial. The download file includes both bathymery examples(not buzzbay) and initlatlon/gps viewer.
The branch at my fork will include Buzzbay and some puerto rico and minor adjustings for epic-daug if needed.
In Field-Robotics-Lab/glider_hybrid_whoi#66, the pre-release I was hoping to get it tested and merged after usjng the simulator as it ia for the puertorico, the target repo is changed from Field-Robotics-Lab/dave to woensugchoi/dave