Initial attempt at cohort logic (still untested)
added acquire count logic and some comments
Removed (what I think is) an unnecessary memory fence
build: Fix regression introduced by MingW32 port.
regressions: Remove unnecessary include.
Merge branch 'master' of https://github.com/sbahra/ck into cohort
testing: Added validation test for cohorts.
gitignore: Removed ck_cohort validation binary from git
cleanup: ck_cohort validation test

Removed unnecessary includes and fixed shadowed variable warning.
testing: ck_cohort validation

The ck_cohort validation test had an error that would cause an uneven distribution of threads among cohorts when the affinity delta was set above 1.
ck_spinlock: Add ticket lock with trylock operation.

Upon popular request, added a variant of the ticket spinlock
with trylock support. This is pending additional verification
on other architectures besides x86*. It is still unclear whether
this implementation will be the default as it is has slower
fast path.

Add trylock support to the ck_spinlock validation tests.
It currently only tests ck_spinlock_ticket_t trylock
functionality if available.
ck_spinlock: Only enable trylock path for TSO architectures at the moment.
ck_pr/gcc: ck_pr_fence_load_depends should be heavy-weight on catch-all target.
ck_fifo: Get rid of load_depends usage for now.

Until a target pops up with a requirement for load_depends(),
the cost is not worth it for now.
testing: Added latency test for ck_cohort
testing: Added throughput test for ck_cohort
whitespace: Added missing space to usage message
cleanup: Removed unnecessary code copied from ck_spinlock's throughput test
ck_pflock: Phase-fair read-write lock implementation.

John Wittrock has contributed a phase-fair reader-writer
lock implementation. These locks allow phase fairness
guarantees between readers and writers. This work includes
additional changes and clean-up.

Follow-up work is expected.

Thanks to John Wittrock for patches and Professor Gabriel
Parmer (http://www.seas.gwu.edu/~gparmer/) for advising.
regressions: Add ck_pflock to make check target.