Remove old docs, rename docs_new to docs

It would be probably good idea to also remove tools/docgen.py and
asciidoc.mk, but asciidoc.mk is still mentioned under `cloud/doc`, which
may contain some useful info which we'll need at least to review before
removing.

PUBLISHED_FROM=faf454d4c52a2f07ea8ac084cf0bd11a0c9c9b3b

docs/c-api/net.h/mg_set_timer.md

@@ -0,0 +1,31 @@
+---
+title: "mg_set_timer()"
+decl_name: "mg_set_timer"
+symbol_kind: "func"
+signature: |
+  double mg_set_timer(struct mg_connection *c, double timestamp);
+---
+
+Schedule MG_EV_TIMER event to be delivered at `timestamp` time.
+`timestamp` is a UNIX time (a number of seconds since Epoch). It is
+`double` instead of `time_t` to allow for sub-second precision.
+Return the old timer value.
+
+Example: set connect timeout to 1.5 seconds:
+
+```
+ c = mg_connect(&mgr, "cesanta.com", ev_handler);
+ mg_set_timer(c, mg_time() + 1.5);
+ ...
+
+ void ev_handler(struct mg_connection *c, int ev, void *ev_data) {
+ switch (ev) {
+   case MG_EV_CONNECT:
+     mg_set_timer(c, 0);  // Clear connect timer
+     break;
+   case MG_EV_TIMER:
+     log("Connect timeout");
+     c->flags |= MG_F_CLOSE_IMMEDIATELY;
+     break;
+``` 
+