fix incorrect gene add error on empty query (#910)

* fix add gene button

* make bulk add case insensitive

* increase performance, incl memoizing

* change which lists are memoized

* improve hash to use ID from dataframe column

* Add requested fixes, and actually make bulk add work

* add default result to empty gene query

* replace with unicode ellipses

* change empty message

client/src/components/geneExpression/index.js

@@ -259,6 +259,7 @@ class GeneExpression extends React.Component {
                   /* this happens on 'enter' */
                   this.handleClick(g);
                 }}
+                initialContent={<MenuItem disabled text="Enter a gene…" />}
                 inputProps={{ "data-testid": "gene-search" }}
                 inputValueRenderer={g => {
                   return "";