Setting verse key by text

Add the ability to set a very key by text
Make the main.rs iterate random verses in John 3

src/cxx/module.h

@@ -20,4 +20,8 @@ class Module {
                 (const char*) this->module->stripText()
             );
         }
+
+        void set_key_text(const rust::String& keyText) {
+            this->module->setKeyText(std::string(keyText).c_str());
+        }
 };