Different behaviour between old strsplit, strjoin and newest

[monikajaskolka]

The strsplit function was introduced by MathWorks in 2017b, while the strjoin function was introduced in 2013b. Our tools were created initially with 2011b, and we would like to keep them backward compatible. However, newer versions of these functions as provided by MathWorks have different behaviour than the ones we provided. Our functions need to be updated so that the behaviour remains the same with what MathWorks provides. Otherwise, if you include ours on the Matlab path, our will overshadow the built-in scripts, any tool (including those not developed by us) will use our functions, and this will cause their scripts to crash because of the difference in behaviour.