* FPDoc 3.3.X changed the syntax for the --footer argument. It uses an ''@' prefix for file names and treats anythine else as text for the footer.. build_lcl_docs did not handle that syntax. Since we do not know which version of FPDoc will be used, we must handle both.
* Accepts --footer=filename.ext for 3.2.X.
* Accepts --footer=@filename.ext for 3.3.X.
* Accepts --footer="Your text here" for 3.3.X.
* File name expansion and validation occurs in the setter for TFPDocRun.FooterFilename.
* Modifies README.txt and all of the script files (.bat, .sh) to document requirements and usage.
