C++ Network Library Code

Adding default User-Agent header in case a User-Agent header doesn't already exist in the request object. I also moved the test for the correct construction of an http request to http_message_test.cpp from http_1_0_test.cpp.

Note: No unit test implemented for this feature; should be doable in the Python CGI script.

Updated documentation.

Fixes for building on GCC 4.2.3 in Ubuntu.

Changes
- Using correct string traits to get the correct type for the string to use based on the tag.
- Using safe(r) string processing methods for handling header lines from the HTTP response.
- basic_response<> now contains version(), status(), and status_message().

TODO:
- multi-line headers processing
- multi-part message posting
- change from multi-map to vector to preserve request header ordering?

Using Boost.Range for iterator ranges instead of a plain pair of integers.

Initial documentation import.

Creating branch for documentation changes.

Adding simple HTTP client example and Jamfile.

Further refactoring of HTTP client that now exposes three new API calls: PUT, DELETE, and POST.

Refactoring HTTP Client internals and added 'head' support.