FIXED: Disable atom-gc during PL_cleanup() to avoid calling hooks into
foreign libraries that may be unloaded.
Updated semweb and http
Updated pldoc
MODIFIED: removed (undocumented) attribute_goal/2 hook, making
attribute_goals//1 the only way to project attributes

Previously, attribute_goal/2 was supported (though never documented
and therefore not used anywhere) as well. Experience has shown that
the DCG version is the only interface that is needed in practice. It
also leads to more elegant code when several goals are produced.
ADDED: library(sandbox): get_attrs/2 and term_attvars/2 are safe.
ADDED: library(sandbox): declare copy_term/3 safe.  Markus Triska.
Updated http
DOC: explain error conditions of nb_* predicates.
To allow for the optimisation that H_VOID, H_POP is replaced with just H_POP, change skipArgs to tolerate unbalanced H_POP
Document dict sorting issues and add a test case for them.
Updated http
Updated http
Preparing version 7.1.27
PORT: Fix for os/pl-rc.c dependencies.  Abramo Bagnara.
Updated http
DOC: get_dict/5  cleanup after comments from Wouter Beek.
FIXED: Attempt to perform meta-argument expansion for locally
defined	non-meta predicates that are also available as globally
defined meta-predicates.