Update to latest trace viewer

Upstream trace viewer has changed substantially since last pull.

First, the old flattening into js + css + html workflow has been replaced with
a new flatten into single html file workflow.

Second, trace viewer has moved to git.

Some pieces that were previously only in systrace are now upstream as well.
In particular, minification is now upstream. Thus, the minifying features in
systrace can be removed.

Change-Id: Ibc6a46fa3dccff8b771a95aae1909cf178157264
diff --git a/.gitignore b/.gitignore
index 362de2e..472fc06 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,4 @@
 *.pyc
 trace.html
 flat_script.js
-.svn/
+trace-viewer/.git/