Add "Change" button links below each step (#306)

Fixes: https://github.com/resin-io/etcher/issues/290
Signed-off-by: Juan Cruz Viotti <jviottidc@gmail.com>

build/css/main.css

@@ -6372,6 +6372,12 @@ body {
   color: #85898c;
   font-size: 10px; }
 
+.btn.step-footer, .step-footer.progress-button {
+  font-size: 12px;
+  border-bottom: 1px dashed;
+  border-radius: 0;
+  padding: 0; }
+
 .separator-xs {
   flex-grow: 0;
   background-color: #64686a;

lib/partials/main.html

@@ -10,7 +10,11 @@
           <p class="step-footer">*supported files: .img, .iso, .zip</p>
         </div>
         <div ng-show="app.selection.hasImage()">
-          <span ng-bind="app.selection.getImage() | basename" ng-click="app.reselectImage()"></span>
+          <div ng-bind="app.selection.getImage() | basename" ng-click="app.reselectImage()"></div>
+
+          <button class="btn btn-link step-footer"
+            ng-click="app.reselectImage()"
+            ng-hide="app.writer.isFlashing()">Change</button>
         </div>
       </div>
     </div>
@@ -39,7 +43,14 @@
           </div>
 
         </div>
-        <div ng-show="app.selection.hasDrive()" ng-bind="app.selection.getDrive().name + ' - ' + app.selection.getDrive().size" ng-click="app.reselectDrive()"></div>
+        <div ng-show="app.selection.hasDrive()">
+          <div ng-bind="app.selection.getDrive().name + ' - ' + app.selection.getDrive().size"
+            ng-click="app.reselectDrive()"></div>
+
+          <button class="btn btn-link step-footer"
+            ng-click="app.reselectDrive()"
+            ng-hide="app.writer.isFlashing()">Change</button>
+        </div>
       </div>
     </div>
   </div>

lib/scss/main.scss

@@ -134,6 +134,13 @@ body {
   font-size: 10px;
 }
 
+.btn.step-footer {
+  font-size: 12px;
+  border-bottom: 1px dashed;
+  border-radius: 0;
+  padding: 0;
+}
+
 .separator-xs {
   flex-grow: 0;
   background-color: darken($color-disabled, 8%);