This PR started as an effort to build on @salhus's #685 to move the 'temp' directory creation into the $CASE directory for each run, and morphed into a few more things:

• moved the 'temp' directory creation into the $CASE directory for each run
• updated WEC-Sim to R2020a (i.e. saved Library in R2020a) to align with WEC-Sim tests, now supporting R2020a and newer
• renamed activate_wecsim and deactivate_wecsim to addWecSimSource and removeWecSimSource for camelCase compliance.
• renamed wecSimInitialize --> initializeWecSim and wecSimStopFunction --> stopWecSim for consistency.
• updated RM3FromSimulink example to have simu.rampTime = 100s from custom input
• removed wecSimStartup and will use addWecSimSource instead
• updated docs to reflect above changes

Note:
Several of these name changes were to reduce the number of autocomplete options when you type wecSim into the command window. Ideally, anything that starts with wecSim is a script that executes WEC-Sim, e.g. wecSim, wecSimMCR, wecSimPCT, wecSimFcn. I'm on the fence about wecSimTest, thoughts?