Delete obsolete procedures and modules from the standard library.

library/array.m:
library/array2d.m:
library/bitmap.m:
library/store.m:
library/thread.semaphore.m:
library/version_array2d.m:
library/version_bitmap.m:
library/version_hash_table.m:
library/version_store.m:
	Delete predicates that were deprecated in Mercury 13.05 and before.

library/version_array.m
	Delete the deprecated function new/2.

	Deprecate unsafe_new/2	and unsafe_init/2 to replace it.
	(We had overlooked this previously.)

library/string.m:
	Delete the deprecated function set_char_char/3.
	(We will leave the other deprecated procedures in this module
	for at least another release.)

library/svlist.m:
library/svpqueue.m:
library/svstack.m:
	Delete these modules: they were only ever needed as a transitional
	mechanism.

library/library.m:
	Conform to the above changes.

doc/Mmakefile:
	Unrelated change: delete references to files that have been
	deleted since we moved to git.

tests/hard_coded/*/*.m
tests/tabling/*.m:
	Update test cases where they made use of predicates that have
	now been deleted from the standard library.