Include tags in GPX success and failure mails. Closes #480.

app/views/notifier/_gpx_description.rhtml

@@ -0,0 +1,14 @@
+Hi,
+
+It looks like your GPX file
+
+  <%= @trace_name %>
+
+with the description 
+
+  <%= @trace_description %>
+<% if @trace_tags.length>0 %>
+and the following tags:
+<% @trace_tags.each do |tag| %>
+  <%= tag.tag.rstrip %><% end %><% else %>
+and no tags.<% end %>

app/views/notifier/gpx_failure.rhtml

@@ -1,9 +1,4 @@
-Hi,
-
-It looks like your GPX file
-
-  <%= @trace_name %>
-
+<%= render :partial => "gpx_description" %>
 failed to import. Here's the error:
 
   <%= @error %>

app/views/notifier/gpx_success.rhtml

@@ -1,8 +1,3 @@
-Hi,
-
-It looks like your GPX file
-
-  <%= @trace_name %>
-
+<%= render :partial => "gpx_description" %>
 loaded successfully with <%= @trace_points %> out of a possible
 <%= @possible_points %> points.