Add libhv and test http client

vendor/libhv/include/hv/nlog.h

@@ -0,0 +1,44 @@
+#ifndef HV_NLOG_H_
+#define HV_NLOG_H_
+
+// nlog: extend hlog use hloop
+
+/* you can recv log by:
+ * Windows: telnet ip port
+ * Linux: nc ip port
+ */
+
+/*
+ * @see examples/hloop_test.c
+#include "hlog.h"
+#include "nlog.h"
+
+void timer_write_log(htimer_t* timer) {
+    static int cnt = 0;
+    hlogi("[%d] Do you recv me?", ++cnt);
+}
+
+int main() {
+    hloop_t* loop = hloop_new(0);
+    hlog_set_handler(network_logger);
+    nlog_listen(loop, DEFAULT_LOG_PORT);
+    htimer_add(loop, timer_write_log, 1000, INFINITE);
+    hloop_run(loop);
+    hloop_free(&loop);
+}
+ */
+
+
+#include "hexport.h"
+#include "hloop.h"
+
+#define DEFAULT_LOG_PORT    10514
+
+BEGIN_EXTERN_C
+
+HV_EXPORT void network_logger(int loglevel, const char* buf, int len);
+HV_EXPORT hio_t* nlog_listen(hloop_t* loop, int port);
+
+END_EXTERN_C
+
+#endif // HV_NLOG_H_