Fixed missing [endsect] and shallowed a bit the Notes section.
Massive but simple changes:

- Removed all tabs
- Changed all Doxygen @cond/@endcond tags with preprocessor sections, as Doxygen still has some problems when parsing this code. This also makes unmatched Doxygen sections a compilation error, which is easier to detect.
Renamved variable "hz" as it conflicts with AIX's system variable.
Trac #10229: Compiling errors in interprocess\detail\os_file_functions.hpp
Updated Jamfile.v2 with new macros for Doxygen and update changelog.
Fixed typo in interprocess.qbk
Reorganized Doxygen marks to obtain a better header reference
fix memory barriers in atomic operations
Merge branch 'master' of https://github.com/DonOregano/interprocess into DonOregano-master
Merge branch 'DonOregano-master' into develop
Use ___sync_synchronize instead of ___atomic as the later is only available in latest builds.