Added a passing test case to cover issue #53.

From: https://github.com/cjerdonek/pystache/commit/7e130676d3523db4e936e5f8f726c1493b2cbd31
Into: issue_53

Adds a test case to cover issue #53.

Conflicts:
	tests/test_pystache.py

Markupsafe can now be turned on and off (for testing purposes).
The unit tests now run test_pystache.py twice if markupsafe is
enabled: once with and once without.  Moreover, all unit tests
now pass.  Previously, one test case in test_pystache.py failed
with markupsafe enabled.

The above change was initially made for testing purpose.  The unit
tests now run the test cases in test_pystache.py twice if markupsafe
is available: once with markupsafe enabled and once without.  All
unit tests now pass using markupsafe (there was previously one
failing test in test_pystache.py: test_non_strings).

Added a unit test to show that the issue is no longer present:
section list items do have access to the parent context.

Template and View classes now support disabling HTML escaping.

 * Used re.split() instead of re.search() to avoid string slicing.
 * Used "".join() once instead of concatenating strings.
 * Removed the need for repeating logic on loop exit (i.e. an additional
   application of self._render_tags(template) and output += ...).

From: https://github.com/jakearchibald/pystache/commit/a936076fd5c06f49c8a7307060861807d8245ffe
Into: issue_46

The failed unit test now passes.

Conflicts:
	pystache/template.py

From: https://github.com/jakearchibald/pystache/commit/1609163fa0c1fe09f7ece8d87be97f730883de06
Into: issue_46

Adds a failing unit test for issue #46 (and another for a standard lambda case).

Conflicts:
	tests/test_pystache.py

* Used re.split() instead of re.search() to avoid string slicing.
* Used one "".join() instead of repeated string concatenation.
* Avoided duplicate logic on loop exit (i.e. output += template).

From: https://github.com/jakearchibald/pystache/commit/3e453f8207ba62dec63b106f381340001b11e74a
Into: issue_44

From: https://github.com/jakearchibald/pystache/commit/9923bef5008dd901f90527f18e1ac7d0df30a890
Into: issue_44

Adds two failing unit tests.

Conflicts:
	tests/test_pystache.py

This also completes the milestone: "Template class should not depend on the
View class."