add pypy to travis testing, and document the reasoning behind the previous changeset.

Author: ikirudennis

.travis.yml

@@ -5,9 +5,11 @@ python:
   - "3.2"
   - "3.3"
   - "3.4"
+  - "pypy"
 # command to install dependencies
 install:
   - pip install -r requirements.txt
   - python setup.py -q install
+  - if [[ ! $TRAVIS_PYTHON_VERSION == pypy ]] ; then pip install regex; fi
 # command to run tests
 script: nosetests

textile/core.py

@@ -437,6 +437,10 @@ def hasRawText(self, text):
         True
 
         """
+        # The php version has orders the below list of tags differently.  The
+        # important thing to note here is that the pre must occur before the
+        # p or else the regex module doesn't properly match pre-s. It only
+        # matches the p in pre.
         r = re.compile(r'<(pre|p|blockquote|div|form|table|ul|ol|dl|h[1-6])[^>]*?>.*</\1>',
                        re.S).sub('', text.strip()).strip()
         r = re.compile(r'<(hr|br)[^>]*?/>').sub('', r)