ck_hs: Simplify marshal path for inserted pointer.

ck_hs_marshal function has been added which mutates
pointer to appropriate representation for insertion.
doc: Fix argument reference in ck_hs_put manual page.
doc: Fix argument reference in ck_hs_set manual page.
ck_hs: Add atomic swap operation (requires existence).
ck_hs: Existence requires generation check.

It is possible for a defragmenting set or swap operation
to set a tombstone. If the probe sequence does not encounter
an empty slot and hits maximum write-side probe limit first
for it to fail to reprobe defragmenting store.
ck_hs: Prototype for new ck_hs_fas operation.
regressions: Testing of ck_hs_fas functionality.
doc: Add ck_hs_fas manual page.
doc: Update ck_hs_fas title.
doc: Add cross-references to ck_hs_fas.
doc: Enable ck_hs_fas manual page compression.
ck_hs: Remove unused return value from ck_hs_fas.
regressions: Fix uninitialized usage in ck_hs parallel_bytestring.
ck_cc: Add branch execution hint support for GCC.
ck_hs: Universally use slot as unit for probe limit optimization.
ck_hs: Branch simplification on fast path.

Take advantage of probe function invariant
(object != NULL) -> (slot != NULL).
build: Bump version for next release.
regressions: Lower wait factor for ck_ticket_pb.
ck_spinlock: Apply modulo arithmetic to proportional back-off ticket lock.
ck_spinlock: Remove erroneous mask usage for non-x86 targets.