v0.3.1

Major Updates:

• Removed vwr package dependency in Shiny app as package has been removed from CRAN, replacing code with stringdist functions. This may fix instances of the Shiny app failing to load.
• Can now pass arguments via ... to control_for_map().

Minor Updates:

• S3 object printing will print "?" if no splits defined.
• Changed control_for_map() documentation to use stringdist instead of vwr.
• More informative errors if no splits or controls are defined.
• New tests for errors.
• New tests for split_random().
• New tests for passing arguments to control_for_map() via ....
• New tests for effects of function calls order in pipeline.
• Updated fontawesome icons in Shiny app.