add http_client library, using libcurl

take out common http entities to http_common dir

libs/main/containers/pideque.h

@@ -2679,7 +2679,7 @@ private:
 				fprintf(stderr, "error with PIDeque<%s>::alloc\n", __PIP_TYPENAME__(T));
 			}
 #endif
-			assert(p_d);
+			assert(new_data);
 			pid_data  = new_data;
 			pid_rsize = new_rsize;
 		}

libs/main/containers/pivector.h

@@ -2556,7 +2556,7 @@ private:
 			fprintf(stderr, "error with PIVector<%s>::alloc\n", __PIP_TYPENAME__(T));
 		}
 #endif
-		assert(p_d);
+		assert(new_data);
 		piv_data  = new_data;
 		piv_rsize = new_rsize;
 	}