Cubist 0.6.0

• A new control option, strip_time_stamps, is used to remove date/time and duration information for better reproducability. (#63)

• An error is thrown if a data or data/time column is passed.

• Switched from base R stop() and warning() to cli's cli_abort() and cli_warn() for improved error messages with better formatting and context.

• Fixed compiler warnings for unused variables in C source code.