Upgrade to coverage 3.7.1 and have it auto-build itself on first use.

third_party/coverage-3.7.1/coverage/htmlfiles/pyfile.html

Index: third_party/coverage-3.7.1/coverage/htmlfiles/pyfile.html
diff --git a/third_party/coverage-3.6/coverage/htmlfiles/pyfile.html b/third_party/coverage-3.7.1/coverage/htmlfiles/pyfile.html
similarity index 98%
rename from third_party/coverage-3.6/coverage/htmlfiles/pyfile.html
rename to third_party/coverage-3.7.1/coverage/htmlfiles/pyfile.html
index 525939f827090b67b41ff81d2c2c84ff7ef90e1a..88c158dd41de934282d3e464529a0d563b1f3343 100644
--- a/third_party/coverage-3.6/coverage/htmlfiles/pyfile.html
+++ b/third_party/coverage-3.7.1/coverage/htmlfiles/pyfile.html
@@ -10,7 +10,7 @@
     {% if extra_css %}
         <link rel='stylesheet' href='{{ extra_css }}' type='text/css'>
     {% endif %}
-    <script type='text/javascript' src='jquery-1.4.3.min.js'></script>
+    <script type='text/javascript' src='jquery.min.js'></script>
     <script type='text/javascript' src='jquery.hotkeys.js'></script>
     <script type='text/javascript' src='jquery.isonscreen.js'></script>
     <script type='text/javascript' src='coverage_html.js'></script>