Improvement in the look and feel of the whole application

Changed the SCSS/CSS for the below third party libraries to adopt the
new look 'n' feel:
- wcDocker
- Alertify dialogs, and notifications
- AciTree
- Bootstrap Navbar
- Bootstrap Tabs
- Bootstrap Drop-Down menu
- Backgrid
- Select2

Adopated the new the look 'n' feel for the dialogs, wizard, properties,
tab panels, tabs, fieldset, subnode control, spinner control, HTML
table, and other form controls.

- Font is changed to Roboto
- Using SCSS variables to define the look 'n' feel
- Designer background images for the Login, and Forget password pages in
  'web' mode
- Improved the look 'n' feel for the key selection in the preferences
  dialog
- Table classes consistency changes across the application
- File Open and Save dialog list view changes

Author(s): Aditya Toshniwal & Khushboo Vashi

web/pgadmin/misc/statistics/static/js/statistics.js

@@ -86,7 +86,7 @@ define('misc.statistics', [
             includeDate: false, includeTime: true, includeMilli: true
           }) */
     },
-    GRID_CLASSES = 'backgrid presentation table backgrid-striped table-bordered table-hover',
+    GRID_CLASSES = 'backgrid presentation table table-bordered table-noouter-border table-hover',
     wcDocker = window.wcDocker;
 
   _.extend(
@@ -257,6 +257,7 @@ define('misc.statistics', [
               }
 
               self.grid = new Backgrid.Grid({
+                emptyText: 'No data found',
                 columns: self.columns,
                 collection: self.collection,
                 className: GRID_CLASSES,