any-of: now throws an error when no wrapped plugins configured (ref. #21)

plugins/any-of.js

@@ -29,6 +29,11 @@
         // merge the defaults with settings from LibResilientConfig
         let config = {...defaultConfig, ...init}
         
+        // reality check: if no wrapped plugin configured, complain
+        if (config.uses.length < 1) {
+            throw new Error("No wrapped plugins configured!")
+        }
+        
         /**
          * getting content using regular HTTP(S) fetch()
          */