Add sidebar tab with route analysis data

- adds a new analysis tab in the sidebar
- the analysis tab shows length distribution for different way types, surface, and smoothness
- table rows can be hovered/clicked to highlight the according segments on the map (similar behaviour as the detailed data table)
- localization is implemented for `de` and `en`
- the method for finding segment edges was extracted from `js/control/TrackMessages.js` into `js/util/TrackEdges.js` as it's used in the new analysis class too (the Gulp config was changed to reflect that)

Notes:

I had the idea to use the *DataTable* plugin for rendering the tables but decided against it. The only meaningful way to sort such a table is by the length column and that's already the case. So it's just three plain, old HTML tables, rendered by jQuery.

For meaningful statistics the `processUnusedTags` setting has to be enabled in the routing profile. Only in this case the BRouter backend includes all needed tags (`highway`, `surface`, and `smoothness`) for *every* route segment in the response. I’ve enabled that setting for all profiles at my BRouter-web instance at <https://brouter.m11n.de/>.

index.html

@@ -573,6 +573,11 @@
                             ><i class="fa fa-table"></i
                         ></a>
                     </li>
+                    <li>
+                        <a href="#tab_statistics" role="tab" data-i18n="[title]sidebar.analysis.title" title="Analysis"
+                            ><i class="fa fa-pie-chart"></i
+                        ></a>
+                    </li>
                 </ul>
             </div>
 
@@ -764,6 +769,14 @@
                             </h1>
                             <div id="itinerary" class="flexcolumn flexgrow"></div>
                         </div>
+
+                        <div class="leaflet-sidebar-pane" id="tab_statistics">
+                            <h1 class="leaflet-sidebar-header">
+                                <span data-i18n="sidebar.analysis.title">Analysis</span>
+                                <span class="leaflet-sidebar-close"><i class="fa fa-caret-right"></i></span>
+                            </h1>
+                            <div id="track_statistics" class="flexcolumn flexgrow"></div>
+                        </div>
                     </div>
                 </div>
             </div>