README.md: fixed links to benchmarks, slight updates
UNTESTED started adding support for hybrid hardware/software transaction
EXPERIMENTAL added hardware transaction macros stmx::hw-atomic and stmx::hw-atomic2.
Unfinished and API will change, but they already show their strengths (very high performance)
and weaknesses (need to duplicate all the code, CONSing causes aborts with probability > 99.99%)