fixed bug [4](https://github.com/cosmos72/stmx/issues/4) - test suite sometimes hangs on ECL
the fix is: do not use "trivial" memory barriers on ECL.
Bugfix: postponed sanity check of (bordeaux-threads:join-thread) until a thread is actually started.
Partially fixes bug [5](https://github.com/cosmos72/stmx/issues/5) on ECL.

Not a complete fix due to a known ECL bug triggered with bordeaux-threads 0.8.3, see:
http://permalink.gmane.org/gmane.lisp.bordeaux-threads.devel/212
http://sourceforge.net/p/ecls/bugs/261/

The remaining issue is:
-------------------------------------------------------------------------------
There is no problem when bordeaux-threads is compiled
for the first time, however thereafter loading from fasls will result in

    Condition of type: BORDEAUX-MP-CONDITION
    There is no support for this method on this implementation.
-------------------------------------------------------------------------------
Removed partial fix for ECL bug
http://permalink.gmane.org/gmane.lisp.bordeaux-threads.devel/212
as it only slightly postponed the known error
    Condition of type: BORDEAUX-MP-CONDITION
    There is no support for this method on this implementation.

The correct solution is to upgrade ECL to a version released on
19 Jun 2013 or later (git commit 914ce253d1d9e52df684dfacc554167b3f100ce7 or
later).

A temporary workaround is to quit ECL, remove all cached FASL files
from ~/.cache/common-lisp/ecl-*, start a new ECL and finally load STMX and its
dependencies with (ql:quickload "stmx")
fixed incorrect type declarations in functions related to TVAR-VERSION,
they caused TYPE-ERRORs on 32-bit systems when global-clock version
exceeded MOST-POSITIVE-FIXNUM
Updated README.md documenting known problems with ECL;
new file doc/supported-systems.md
updated TODO
portability fix: removed SHARED-INITIALIZE method override (not allowed by MOP) to initialize transactional objects, replaced it with method overrides for INITIALIZE-INSTANCE and REINITIALIZE-INSTANCE
updated TODO with latest changes
reduced amount of code to compile when repeatedly running test suite
worked around a CMUCL error while loading STMX
Merge branch 'master' of https://github.com/cosmos72/stmx
cleaned up detection of optional features
more cleanups for CCL and CMUCL