Clip very long branch names to avoid overflow

Repository indexes with huge branch names can see the branch name
overlap with recent commit history or README.md file contents.  This
is caused by the ref list using a "float: left" with a fixed width
specification of 200px.

Reduce the left side padding to 15px to get more space for the
actual branch/tag names while still showing some level of indent
below the Branches and Tags headers. Request overflow hidden with
ellipsis for truncation in the browser.

Expand the lists on the /+refs page to show 500px for each of
the Branches and Tags columns, allowing names clipped on the
repository index page a better chance to be presented without
any clipping after following the "More..." link.

Change-Id: I13a833452b7298ac5d45dc63958f8921649cd464

gitiles-servlet/src/main/resources/com/google/gitiles/static/gitiles.css

diff --git a/gitiles-servlet/src/main/resources/com/google/gitiles/static/gitiles.css b/gitiles-servlet/src/main/resources/com/google/gitiles/static/gitiles.css
index 37e3dca..26130ae 100644
--- a/gitiles-servlet/src/main/resources/com/google/gitiles/static/gitiles.css
+++ b/gitiles-servlet/src/main/resources/com/google/gitiles/static/gitiles.css
@@ -156,6 +156,18 @@
   float: left;
   width: 200px;
 }
+.refs-detail {
+  width: 500px;
+}
+.ref-list {
+  padding-left: 15px;
+  padding-right: 5px;
+}
+.ref-list li {
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
 .ref-list li.head-ref {
   font-weight: bold;
 }

gitiles-servlet/src/main/resources/com/google/gitiles/templates/RefList.soy

diff --git a/gitiles-servlet/src/main/resources/com/google/gitiles/templates/RefList.soy b/gitiles-servlet/src/main/resources/com/google/gitiles/templates/RefList.soy
index e42ee7e..57b1111 100644
--- a/gitiles-servlet/src/main/resources/com/google/gitiles/templates/RefList.soy
+++ b/gitiles-servlet/src/main/resources/com/google/gitiles/templates/RefList.soy
@@ -34,7 +34,7 @@
 {/call}
 
 {if length($branches)}
-  <div class="refs-branches">
+  <div class="refs-branches refs-detail">
     {call .refList}
       {param type: 'Branches' /}
       {param refs: $branches /}
@@ -43,7 +43,7 @@
 {/if}
 
 {if length($tags)}
-  <div class="refs-tags">
+  <div class="refs-tags refs-detail">
     {call .refList}
       {param type: 'Tags' /}
       {param refs: $tags /}