main.c v1.04 (change the arguments global)

Now need not pass the arguments in the function startsws().
net.h v1.05(add function clientwrite)

Add the function clientwrite() declaration.
Modify the declaration of startsws();
http.c v1.02 (fix some bugs)

We don't want the source contain \r and \n. So ignore them when compute
the length.
Now can tolerate blanks after the path (instead of throw a 400 error).
net.c v1.08 (GET request)

The server now can response the GET request.
Just show the file which the client wants.
Add simple 403 and 404 error response.