Restructure dirs

I:

* Moved the HTTP examples to contrib/http_examples
* Added gtest as a submodule under the deps subdirectory
* Replaced the URI code with a new submodule based on the work I've been doing for the last couple of months (breaking changes)
* Configured the project to compile and run on MSVC 2012 and GCC 4.7.2
* Updated any breaking code (limited to the changes in the URI, which turned out to be very little)
* Updated README.rst

The project is still in the same intermediate state (failing tests in the HTTP client, the HTTP server doesn't compile, neither does MIME)

I would suggest the following further changes:

* The logging and mime libraries can be separate submodules
* Add gmock as a submodule
* Implement the HTTP client API according to the design doc