bugfix: lib/sh/local.sh: root_rel_path(): use canon_rel_path instead of rel_path because $1 may be absolute rather than relative to the current dir, so $root_dir needs to be absoluted (which requires $1 to be absoluted as well)

lib/sh/util.sh: support custom $base_dir, which will be run through realpath() to match $path ($PWD, which was used before, did not need to be realpath'd because it was already absolute)

lib/sh/util.sh: moved echo_func alias to stub because it must be embedded in its expanded alias form to work properly

lib/sh/util.sh: declare echo_func as a stub before it's defined, so that functions can use it even if they are defined before it (and its logging functionality will be enabled as soon as it's defined)

lib/sh/util.sh: rel_path(): don't log++ it, and instead only log++ applicable calls of it or its callers. this allows non-internal calls of rel_path() to be logged at the usual log_level.

lib/sh/local.sh: added root_rel_path()

lib/Firefox_bookmarks.reformat.csv: unescape HTML in page's description, such as links to more info. this is necessary to properly render the persistent shells link in the screen > scrollback folder description.

bin/repl: added unescape_html() filter function, which can be specified as the replacement string

bin/repl: support Unicode characters in the matched portion of the string

web/links/index.htm: updated to Firefox bookmarks. `screen`: scrollback: added link to our wiki page on persistent shells, which are a better way to support reconnecting.