Implement Array-enabled for ERROR.TYPE() function
Extract ERROR.TYPE() function tests into separate test file
Extract error function tests into separate test files
And thus complete the implemented Information functions
* First steps toward array-enabling the information functions
Also includes moving unit tests out from Functions and into a separate, dedicated Information folder
* Resolve issue with IF(), branch pruning and calculation cache (ensure that we don't convert the if condition to a bool before we've tested to see if it evaluates to an error)
More refactoring