Remove unused twbs components

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/assets/stylesheets/framework/tw_bootstrap.scss

@@ -32,8 +32,6 @@
 @import "bootstrap/pager";
 @import "bootstrap/labels";
 @import "bootstrap/badges";
-@import "bootstrap/jumbotron";
-@import "bootstrap/thumbnails";
 @import "bootstrap/alerts";
 @import "bootstrap/progress-bars";
 @import "bootstrap/list-group";

app/assets/stylesheets/pages/note_form.scss

@@ -65,7 +65,6 @@
 
 .note-image-attach {
   @extend .col-md-4;
-  @extend .thumbnail;
   margin-left: 45px;
   float: none;
 }