Docs are generated for Mongoose

Comments in headers are changed a bit: removed adoc-specific stuff,
markdown is used instead

PUBLISHED_FROM=9242cce85cc52a47a197d377e7e23804721a6bb5

docs/c-api/http.h/mg_parse_http.md

@@ -0,0 +1,15 @@
+---
+title: "mg_parse_http()"
+decl_name: "mg_parse_http"
+symbol_kind: "func"
+signature: |
+  int mg_parse_http(const char *s, int n, struct http_message *hm, int is_req);
+---
+
+Parse a HTTP message.
+
+`is_req` should be set to 1 if parsing request, 0 if reply.
+
+Return number of bytes parsed. If HTTP message is
+incomplete, `0` is returned. On parse error, negative number is returned. 
+