* -F (force even if gpg fails) option for hide and reveal
* allow 'reveal' to decrypt a subset of files.
* update and regen man pages
* man pages update and improvements
* text about why all files should be hidden at once
* add _warn() and _warn_or_abort()
* tests for -F option
* glob source .sh files in Makefile better
* add comment about issue #238. cleanup error msg.
* test exact case in #253
* disable gnupg doc building on ubuntu-rolling
