Added clearLocalStorage

- Added a UI button that clears local data
 . Useful to clear login credentials, nodelist, lastTx when stuck in some version change bugs

docs/index.html

@@ -91,6 +91,7 @@
                     <p>Don't have FLO credentials?</p>
                     <sm-button onclick="showPopup('sign_up_popup')">Generate FLO credentials</sm-button>
                 </div>
+                <sm-button onclick="clearAllLocalData()">clear local data</sm-button>
             </sm-form>
             <sm-form id="trade_form" class="user-content hide-completely">
                 <div id="flo_exchange_rate" class="grid align-center">

docs/scripts/exchangeAPI.js

@@ -619,4 +619,12 @@ function refreshDataFromBlockchain() {
             resolve(nodes);
         }).catch(error => reject(error));
     })
+}
+
+function clearAllLocalData() {
+    localStorage.removeItem('exchange-nodes');
+    localStorage.removeItem('exchange-lastTx');
+    localStorage.removeItem('exchange-proxy_secret');
+    localStorage.removeItem('exchange-user_ID');
+    location.reload();
 }