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

third_party/coverage-3.7.1/CHANGES.txt

Index: third_party/coverage-3.7.1/CHANGES.txt
diff --git a/third_party/coverage-3.6/CHANGES.txt b/third_party/coverage-3.7.1/CHANGES.txt
similarity index 91%
rename from third_party/coverage-3.6/CHANGES.txt
rename to third_party/coverage-3.7.1/CHANGES.txt
index 9404fc0b9d1333117b1e99e850d4103749b0854c..1e4b888b52c5964a2609a60758bce029278783eb 100644
--- a/third_party/coverage-3.6/CHANGES.txt
+++ b/third_party/coverage-3.7.1/CHANGES.txt
@@ -2,6 +2,71 @@
 Change history for Coverage.py
 ------------------------------
 
+3.7.1 -- 13 December 2013
+-------------------------
+
+- Improved the speed of HTML report generation by about 20%.
+
+- Fixed the mechanism for finding OS-installed static files for the HTML report
+  so that it will actually find OS-installed static files.
+
+
+3.7 --- 6 October 2013
+----------------------
+
+- Added the ``--debug`` switch to ``coverage run``.  It accepts a list of
+  options indicating the type of internal activity to log to stderr.
+
+- Improved the branch coverage facility, fixing `issue 92`_ and `issue 175`_.
+
+- Running code with ``coverage run -m`` now behaves more like Python does,
+  setting sys.path properly, which fixes `issue 207`_ and `issue 242`_.
+
+- Coverage can now run .pyc files directly, closing `issue 264`_.
+
+- Coverage properly supports .pyw files, fixing `issue 261`_.
+
+- Omitting files within a tree specified with the ``source`` option would
+  cause them to be incorrectly marked as unexecuted, as described in
+  `issue 218`_.  This is now fixed.
+
+- When specifying paths to alias together during data combining, you can now
+  specify relative paths, fixing `issue 267`_.
+
+- Most file paths can now be specified with username expansion (``~/src``, or
+  ``~build/src``, for example), and with environment variable expansion
+  (``build/$BUILDNUM/src``).
+
+- Trying to create an XML report with no files to report on, would cause a
+  ZeroDivideError, but no longer does, fixing `issue 250`_.
+
+- When running a threaded program under the Python tracer, coverage no longer
+  issues a spurious warning about the trace function changing: "Trace function
+  changed, measurement is likely wrong: None."  This fixes `issue 164`_.
+
+- Static files necessary for HTML reports are found in system-installed places,
+  to ease OS-level packaging of coverage.py.  Closes `issue 259`_.
+
+- Source files with encoding declarations, but a blank first line, were not
+  decoded properly.  Now they are.  Thanks, Roger Hu.
+
+- The source kit now includes the ``__main__.py`` file in the root coverage
+  directory, fixing `issue 255`_.
+
+.. _issue 92: https://bitbucket.org/ned/coveragepy/issue/92/finally-clauses-arent-treated-properly-in
+.. _issue 164: https://bitbucket.org/ned/coveragepy/issue/164/trace-function-changed-warning-when-using
+.. _issue 175: https://bitbucket.org/ned/coveragepy/issue/175/branch-coverage-gets-confused-in-certain
+.. _issue 207: https://bitbucket.org/ned/coveragepy/issue/207/run-m-cannot-find-module-or-package-in
+.. _issue 242: https://bitbucket.org/ned/coveragepy/issue/242/running-a-two-level-package-doesnt-work
+.. _issue 218: https://bitbucket.org/ned/coveragepy/issue/218/run-command-does-not-respect-the-omit-flag
+.. _issue 250: https://bitbucket.org/ned/coveragepy/issue/250/uncaught-zerodivisionerror-when-generating
+.. _issue 255: https://bitbucket.org/ned/coveragepy/issue/255/directory-level-__main__py-not-included-in
+.. _issue 259: https://bitbucket.org/ned/coveragepy/issue/259/allow-use-of-system-installed-third-party
+.. _issue 261: https://bitbucket.org/ned/coveragepy/issue/261/pyw-files-arent-reported-properly
+.. _issue 264: https://bitbucket.org/ned/coveragepy/issue/264/coverage-wont-run-pyc-files
+.. _issue 267: https://bitbucket.org/ned/coveragepy/issue/267/relative-path-aliases-dont-work
+
+
 Version 3.6 --- 5 January 2013
 ------------------------------
 
@@ -230,7 +295,7 @@ Version 3.5.2b1 --- 29 April 2012
   of the execution environment weren't the same as for
   ``python -m <modulename>``.  This had the unfortunate side-effect of making
   ``coverage run -m unittest discover`` not work if you had tests in a
-  directory named "test".  This fixes `issue 155`_.
+  directory named "test".  This fixes `issue 155`_ and `issue 142`_.
 
 - Now the exit status of your product code is properly used as the process
   status when running ``python -m coverage run ...``.  Thanks, JT Olds.
@@ -239,6 +304,7 @@ Version 3.5.2b1 --- 29 April 2012
   the C tracer function, closing `issue 166`_.
 
 .. _issue 82: https://bitbucket.org/ned/coveragepy/issue/82/tokenerror-when-generating-html-report
+.. _issue 142: https://bitbucket.org/ned/coveragepy/issue/142/executing-python-file-syspath-is-replaced
 .. _issue 155: https://bitbucket.org/ned/coveragepy/issue/155/cant-use-coverage-run-m-unittest-discover
 .. _issue 157: https://bitbucket.org/ned/coveragepy/issue/157/chokes-on-source-files-with-non-utf-8
 .. _issue 166: https://bitbucket.org/ned/coveragepy/issue/166/dont-try-to-compile-c-extension-on-pypy