Remove the use of "using namespace std;" in the webserver module.

[jeandudey]

In this commit i made these changes:

• Remove the use of "using namespace std;".
• Change ::bind to bind. It can be called normally now.
• Removed the include of "sys/sockets.h" in the webserver.cpp file. the include of "sys/sockets.h" is declared first at webserver.h
• Removed condition_variable and queue from the includes section.

[davidrmiller]

Thanks for doing this clean-up. I tested it with g++ on Linux and Cygwin on Windows.

In webserver.cpp on line 151, ref() is now undefined, so we should change that to std::ref().

Also, std::ref() is declared in <functional>. I forgot to #include that header, so some other system header must be including it behind the scenes. To be pedantically correct, we could add #include <functional> to webserver.cpp.

Please feel free to submit an updated pull request, and then I will apply it without modification. Alternatively, I can apply the pull request with modifications, and I'll try to make sure your name appears in the "author" field.

[jeandudey]

I will make the changes. Thanks for the feedback

[davidrmiller]

Thanks for the contribution!