Cosmetic improvements of homeserver and user inputs

Keyboard type for homeserver TextInput changed to url and trailing '/' with potential whitespaces is stripped.
Keyboard type for username changed to e-mail for convenience.

Should resolve: #34 and #64

lib/components/dialogs/simple_dialogs.dart

@@ -8,8 +8,8 @@ class SimpleDialogs {
 
   const SimpleDialogs(this.context);
 
-  Future<String> enterText({
-    String titleText,
+  Future<String> enterText(
+      {String titleText,
       String confirmText,
       String cancelText,
       String hintText,
@@ -18,7 +18,7 @@ class SimpleDialogs {
       String suffixText,
       bool password = false,
       bool multiLine = false,
-  }) async {
+      TextInputType keyboardType}) async {
     var textEditingController = TextEditingController();
     final controller = textEditingController;
     String input;
@@ -38,6 +38,7 @@ class SimpleDialogs {
           maxLines: multiLine ? 3 : 1,
           obscureText: password,
           textInputAction: multiLine ? TextInputAction.newline : null,
+          keyboardType: keyboardType,
           decoration: InputDecoration(
             hintText: hintText,
             labelText: labelText,

lib/views/homeserver_picker.dart

@@ -12,7 +12,8 @@ class HomeserverPicker extends StatelessWidget {
     final homeserver = await SimpleDialogs(context).enterText(
         titleText: L10n.of(context).enterYourHomeserver,
         hintText: Matrix.defaultHomeserver,
-        prefixText: 'https://');
+        prefixText: 'https://',
+        keyboardType: TextInputType.url);
     if (homeserver?.isEmpty ?? true) return;
     _checkHomeserverAction(homeserver, context);
   }
@@ -21,6 +22,13 @@ class HomeserverPicker extends StatelessWidget {
     if (!homeserver.startsWith('https://')) {
       homeserver = 'https://$homeserver';
     }
+
+    // removes trailing spaces and slash from url if present (api errors on it)
+    homeserver = homeserver.trim();
+    if (homeserver.endsWith('/')) {
+      homeserver = homeserver.substring(0, homeserver.length - 1);
+    }
+
     final success = await SimpleDialogs(context).tryRequestWithLoadingDialog(
         Matrix.of(context).client.checkServer(homeserver));
     if (success != false) {

lib/views/login.dart

@@ -131,6 +131,7 @@ class _LoginState extends State<Login> {
                 readOnly: loading,
                 autocorrect: false,
                 autofocus: true,
+                keyboardType: TextInputType.emailAddress,
                 onChanged: (t) => _checkWellKnownWithCoolDown(t, context),
                 controller: usernameController,
                 decoration: InputDecoration(