FPHSA: add argument FOUND_VAR instead of USE_ORIGINAL_CASE

In the new mode FPHSA now accepts a FOUND_VAR option, which can be
set either to ExactCase_FOUND or UPPERCASE_FOUND, no other values
are accepted.
Also add tests for that, including failure.

Alex
FPHSA: improve documentation

Alex
Merge topic 'FPHSA_FOUND_VAR_OPTION' into next

fedcd8d FPHSA: improve documentation
ebbf9b6 FPHSA: add argument FOUND_VAR instead of USE_ORIGINAL_CASE