CDC and yaml_bench makefile now always compile with debug

symbols. yaml_bench can now repeat the benchmark many times in a
single run. yaml_gen can now disable collection keys in mappings.

examples/yaml_gen/config.yaml

@@ -1,8 +1,9 @@
 root-type:              seq
 documents:              2
 complex-keys:           false
-min-nodes-per-document: 512 
-encoding:               utf-32
+collection-keys:        false
+min-nodes-per-document: 65536 
+encoding:               utf-8
 indent:                 4
 text-width:             40
 

examples/yaml_gen/yaml_gen.d

@@ -155,7 +155,8 @@ Node genBinary(bool root = false)
 
 Node nodes(in bool root, Node range, in string tag, in bool set = false)
 {
-    auto types = typesCollection ~ (set ? typesScalarKey : typesScalar);
+    auto types = config["collection-keys"].as!bool ? typesCollection : [];
+    types ~= (set ? typesScalarKey : typesScalar);
 
     Node[] nodes;
     if(root)