Clean up debugger server

    * Remove perpetual innner while loop
    * Macro to TRACE_DEBUGGER_SERVER
clearBuffers() and JSBDebug_BufferWrite() will both immediately write data in the output buffer to the socket.

    * Note : comments in the code say that locking is not an issue. This should be reviewed.
Set socket option SO_NOSIGPIPE
Match CocosPlayer's JSB_DEBUGGER_PORT
Eval and log

 * dbg.log is the same as log
 * Eval stringifies JSON