Dropped Dynawo 1.6.x from testing (#188)

Author: casella

configs/conf.json

@@ -266,11 +266,6 @@
     "library":"Dynawo",
     "extraCustomCommands":["setCommandLineOptions(\"--allowNonStandardModelica=implicitParameterStartAttribute\");"]
   },
-  {
-    "library":"Dynawo",
-    "libraryVersion":"maint.1.6.x",
-    "libraryVersionNameForTests":"1.6.1"
-  },
   {
     "library":"Dynawo",
     "libraryVersion":"master",