General code clean up to support a clean XS/MD version 4.x

Minor changes to comment formatting
SimpleMailbox processor has been removed in favour of the built in one,
everything appears to be working ok in Mono now.
minor update to debugging section and list of maintainers
Merge pull request #128 from 7sharp9/patch-1

minor update to debugging section and list of maintainers
Merge pull request #129 from 7sharp9/master

General cleanup of code and #ifdefs