This function is an update of an old one (submitted in 2013) I decided to delete. This version is cleaner, shorter and more efficient than the previous one.
It recursively searches for specified file names and extensions (with or without respect to letter case) in a given directory and its sub-directories.
Example: findFileInFolder(pwd, {'.m', '.zip', '.mat'}) match all files with the corresponding extensions ('.m', '.zip', '.mat') in the current directory
More information in the m-file