tweak transition

docs/assets/css/bootstrap.css

@@ -5059,10 +5059,10 @@ input[type="submit"].btn.btn-mini {
   -webkit-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.055);
      -moz-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.055);
           box-shadow: 0 1px 3px rgba(0, 0, 0, 0.055);
-  -webkit-transition: all 0.2s linear;
-     -moz-transition: all 0.2s linear;
-       -o-transition: all 0.2s linear;
-          transition: all 0.2s linear;
+  -webkit-transition: all 0.2s ease-in-out;
+     -moz-transition: all 0.2s ease-in-out;
+       -o-transition: all 0.2s ease-in-out;
+          transition: all 0.2s ease-in-out;
 }
 
 a.thumbnail:hover {

docs/assets/js/bootstrap.js

@@ -1918,3 +1918,107 @@
   })
 
 }(window.jQuery);
+/* ==========================================================
+ * bootstrap-affix.js v2.1.0
+ * http://twitter.github.com/bootstrap/javascript.html#affix
+ * ==========================================================
+ * Copyright 2012 Twitter, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ========================================================== */
+
+
+!function ($) {
+
+  "use strict"; // jshint ;_;
+
+
+ /* AFFIX CLASS DEFINITION
+  * ====================== */
+
+  var Affix = function (element, options) {
+    this.options = $.extend({}, $.fn.affix.defaults, options)
+    this.$window = $(window).on('scroll.affix.data-api', $.proxy(this.checkPosition, this))
+    this.$element = $(element)
+    this.checkPosition()
+  }
+
+  Affix.prototype.checkPosition = function () {
+    if (!this.$element.is(':visible')) return
+
+    var scrollHeight = $(document).height()
+      , scrollTop = this.$window.scrollTop()
+      , position = this.$element.offset()
+      , offset = this.options.offset
+      , offsetBottom = offset.bottom
+      , offsetTop = offset.top
+      , reset = 'affix affix-top affix-bottom'
+      , affix
+
+    if (typeof offset != 'object') offsetBottom = offsetTop = offset
+    if (typeof offsetTop == 'function') offsetTop = offset.top()
+    if (typeof offsetBottom == 'function') offsetBottom = offset.bottom()
+
+    affix = this.unpin != null && (scrollTop + this.unpin <= position.top) ?
+      false    : offsetBottom != null && (position.top + this.$element.height() >= scrollHeight - offsetBottom) ?
+      'bottom' : offsetTop != null && scrollTop <= offsetTop ?
+      'top'    : false
+
+    if (this.affixed === affix) return
+
+    this.affixed = affix
+    this.unpin = affix == 'bottom' ? position.top - scrollTop : null
+
+    this.$element.removeClass(reset).addClass('affix' + (affix ? '-' + affix : ''))
+  }
+
+
+ /* AFFIX PLUGIN DEFINITION
+  * ======================= */
+
+  $.fn.affix = function (option) {
+    return this.each(function () {
+      var $this = $(this)
+        , data = $this.data('affix')
+        , options = typeof option == 'object' && option
+      if (!data) $this.data('affix', (data = new Affix(this, options)))
+      if (typeof option == 'string') data[option]()
+    })
+  }
+
+  $.fn.affix.Constructor = Affix
+
+  $.fn.affix.defaults = {
+    offset: 0
+  }
+
+
+ /* AFFIX DATA-API
+  * ============== */
+
+  $(window).on('load', function () {
+    $('[data-spy="affix"]').each(function () {
+      var $spy = $(this)
+        , data = $spy.data()
+
+      data.offset = data.offset || {}
+
+      data.offsetBottom && (data.offset.bottom = data.offsetBottom)
+      data.offsetTop && (data.offset.top = data.offsetTop)
+
+      $spy.affix(data)
+    })
+  })
+
+
+}(window.jQuery);

less/thumbnails.less

@@ -31,7 +31,7 @@
   border: 1px solid #ddd;
   .border-radius(4px);
   .box-shadow(0 1px 3px rgba(0,0,0,.055));
-  .transition(all .2s linear);
+  .transition(all .2s ease-in-out);
 }
 // Add a hover state for linked versions only
 a.thumbnail:hover {