sample implementation of ACT-1738
try to add test case for MDC. Not working yet
complete implementation of ACT-1738
Merge remote-tracking branch 'upstream/master' into act-1738
add files for act-1738
add files for act-1738
add comments
update userguide
enhance MDC documentation
correct typo
repackage LogMDC
Merge branch 'act-1738' of https://github.com/smirzai/Activiti
Small change to MDC unit test