sys-apps/less: lesspipe: minor improvements

sys-apps/less: lesspipe: minor improvements

* Add/update copyright/license headers.
* Test whether LESSDEBUG is set rather than its value
* Fix `stat` usage on pseudo paths (e.g. URIs) & names that start with -
* Add a .json print handler via python
* Process https:// URIs like http://
* Try elinks in addition to & before other CLI browsers
* Tweak quoting in a few places as shellcheck highlighted
* Check $# -eq 0 so we don't treat "" as missing arguments
* Don't run lesspipe twice when it fails & LESSDEBUG is enabled

Signed-off-by: Mike Frysinger <vapier@gentoo.org>