Adapt get predict table, renamed present/future climate to observed/projected climate

[merretbuurman]

Renamed two download functions:

• As discussed, renamed download_present_climate_tables() to download_observed_climate_tables()
• As discussed, renamed download_future_climate_tables() to download_projected_climate_tables()

Modified get_predict_table():

• Mainly, replaced list of accepted variables (which was outdated) by a call to the download_env functions.
• Added a check whether input tables exist (because during testing, they didn't exist, and it failed without suitable error message)
• Added some more output messages (will be displayed if quiet=FALSE)
• Added output messages to bash script (will be displayed if quiet=FALSE)
• I tested this locally and it worked.

Furthermore:

• Started adapting some unit tests so that they load local dummy tables instead of downloading tables from server. To be continued.

[JaimeRi]

looks good