Use bootstrap table striping to replace hand-cycled table stripes

This cuts down on the complexity of having to use the `cycle` function
and makes the templates easier to read. CSS-based striping has been
around for many years.

The CSS is in order to keep our custom colour for striped tables.

app/views/traces/_trace.html.erb

@@ -1,6 +1,5 @@
 <tr>
-  <% cl = cycle("table0", "table1") %>
-  <td class="<%= cl %>">
+  <td>
     <% if Settings.status != "gpx_offline" %>
       <% if trace.inserted %>
         <a href="<%= url_for :controller => "traces", :action => "show", :id => trace.id, :display_name => trace.user.display_name %>"><img src="<%= url_for :controller => "traces", :action => "icon", :id => trace.id, :display_name => trace.user.display_name %>" border="0" alt="" /></a>
@@ -9,7 +8,7 @@
       <% end %>
     <% end %>
   </td>
-  <td class="<%= cl %>"><%= link_to trace.name, :controller => "traces", :action => "show", :display_name => trace.user.display_name, :id => trace.id %>
+  <td><%= link_to trace.name, :controller => "traces", :action => "show", :display_name => trace.user.display_name, :id => trace.id %>
     <span class="trace_summary" title="<%= trace.timestamp %>"> ...
       <% if trace.inserted %>
         (<%= t ".count_points", :count => trace.size %>)

app/views/traces/index.html.erb

@@ -25,7 +25,7 @@
 <% if @traces.size > 0 %>
   <%= render :partial => "trace_paging_nav" %>
 
-  <table id="trace_list" cellpadding="3">
+  <table id="trace_list" class="table table-borderless table-striped">
     <thead>
       <tr>
         <th></th>