[Fix] Remove all Scenarios, catch empty SMILES, prevent default Package delete (#134)

Co-authored-by: Tim Lorsbach <tim@lorsba.ch>
Reviewed-on: enviPath/enviPy#134

templates/index/index.html

@@ -103,6 +103,7 @@
             var textSmiles = $('#index-form-text-input').val().trim();
 
             if (textSmiles === '') {
+                $(this).prop("disabled", false);
                 return;
             }