C++ Network Library Code

Merged in code from pion-net's HTTPParser and HTTPTypes classes, r405

Merged changes from trunk into http_integration branch (r28 - r:31)

impl/request.hpp: roll back change in include header. Now includes
boost/fusion/container/map.hpp instead of
boost/fusion/sequence/container/map.hpp

Changed include header of fusion::map to conform to current header
locations in the Boost CVS.

Changes:
- boost/network/protocol/http/impl/request.hpp: updating includes to use the correct Fusion include for the map container
- boost/network/protocol/http/client.hpp: removing dependence on std::ostringstream and moving the type of output string stream to be determined by the tag template parameter
- boost/network/message.hpp: adding the default 'ostringstream_type' as an std::ostringstream in the default_ tag
- libs/network/test/http_1_0_test.cpp: additional HTTP 1.0 test for port specified in the URL

Added HTTP integration branch

Moved branch to branches directory.

Created a new branch for the HTTP tests; added basic Quickbook documentation.

Add -lpthread option since Boost.System requires pthread at the linking stage.

Added typename keyword in order to make the code compile on