Quality of life changes for splith function

[franfrutos]

The main update will consists in support more types of analysis and do split-half for multiple variables and ways for efficently repports and communicate results:

• Add difference of difference, average, and more.

• Allows to compute Dprime, Aprime and Bprime for accuracy data.

• Automaticly detect if data are RT or ACC type.

• Possibility of performance split-half for different variables running the function once.

• Enhance visualization and comunication through the possibility of make ready to publish tables and plots.

[franfrutos]

Thanks to this thread (https://codereview.stackexchange.com/questions/70203/an-r-function-for-checking-whether-a-variable-is-binary-or-continuous), and the answer given by the user janos, I include a function that allows to detect if data are continous or binary. That further improves splith function to distinguish if data are RT or ACC type.