Shiny Server Function for Feature Calculation of Function Input

functionInput is a shiny server function which controls all aspects of the FlaccoFunctionInput UI Module. Will be called with callModule.

functionInput(input, output, session, stringsAsFactors)

Arguments

input	[shiny-input] shiny input variable for the specific UI module.
output	[shiny-output object] shiny output variable for the specific UI module.
session	[shiny-session object] shiny session variable for the specific UI module.
stringsAsFactors	[logical(1)] How should strings be treated internally?