core: more (internal) improvements on web_client
core: more (internal) improvements on web_client

* fixed enabling O_NONBLOCK
* call read_some() on response completion in case we'll receive more.

christianparpart/x0,christianparpart/x0,xzero/x0,christianparpart/x0,xzero/x0,christianparpart/x0,xzero/x0,xzero/x0,christianparpart/x0,christianparpart/x0,xzero/x0,christianparpart/x0,xzero/x0