Accepted into Boost - August 20, 2012

NOTE: This revision of the library passed Boost formal review and it was accepted into the Boost libraries (see https://groups.google.com/forum/?fromgroups=#!topic/boost-list/jQ7OjAmos_Y).

1. Using non-fix-spaced font in Full Table of Contents section.
2. Added a couple of notes to the documentation.
3. Changed CONTRACT_MEMBER_BODY(class_type, function_name) to class_type::CONTRACT_MEMBER_BODY(function_name) so the macro can also be used to declare derived classes avoiding using the library syntax even when the base class has contracts.