Closes #277 -- remove unsupported client_fwd.hpp
Closes #129, Closes #279, Closes #27

- Deprecate Synchronous Client implementations (#279)
- Support Streaming body in Client Request (#27)
- Deprecate support for header-only usage (#129)
Closes #313 -- make all client implementations use a non-case-sensitive multimap.
Remove Jamfiles (Closes #316)
Up version to 0.11.0
Update changelog.
Adding more changes to Changelog.
Update references to 0.10 -> 0.11; add ToC link to front page.
Updating documentation for 0.11.0