Reimplement _unescape_entities routine.

</?text:s.*?> entities are not longer escaped.
This functionallity was used when secretary handled plain text
jinja instructions. This now is no longer supported since the
official method to add instructions is through input fields.

secretary.py

@@ -218,6 +218,31 @@ class Renderer(object):
             self.environment.block_end_string
         ))
 
+        self._compile_escape_expressions()
+
+
+    def _compile_escape_expressions(self):
+        # Compiles escape expressions
+        self.escape_map = dict()
+        unescape_rules = {
+            r'>'         : r'>',
+            r'&lt;'         : r'<',
+            r'&amp;'        : r'&',
+            r'&quot;'       : r'"',
+        }
+
+        for key, value in unescape_rules.items():
+            exp = r'(?is)(({0}|{1}).*?)({2})(.*?({3}|{4}))'
+            key = re.compile(exp.format(
+                self.environment.variable_start_string,
+                self.environment.block_start_string,
+                key,
+                self.environment.variable_end_string,
+                self.environment.block_end_string
+            ))
+
+            self.escape_map[key] = r'\1{0}\4'.format(value)
+
 
     def _is_jinja_tag(self, tag):
         """
@@ -366,24 +391,16 @@ class Renderer(object):
             placeholder_parent.removeChild(placeholder)
 
 
-    @staticmethod
-    def _unescape_entities(xml_text):
+    def _unescape_entities(self, xml_text):
         """
-        Strips tags of the form <text:span ...> from inside Jinja elements
-        and unescapes HTML codes for >, <, & and "
+        Unescape '&amp;', '&lt;', '&quot;' and '&gt;' within jinja instructions.
+        The regexs rules used here are compiled in _compile_escape_expressions.
         """
-        unescape_rules = {
-            r'(?is)({([{%])[^%}]*?)(</?text:s.*?>)(.*?[%}]})': r'\1 \4',
-            r'(?is)({([{%])[^%}]*?)(&gt;)(.*?[%}]})'         : r'\1>\4',
-            r'(?is)({([{%])[^%}]*?)(&lt;)(.*?[%}]})'         : r'\1<\4',
-            r'(?is)({([{%])[^%}]*?)(&amp;)(.*?[%}]})'        : r'\1&\4',
-            r'(?is)({([{%])[^%}]*?)(&quot;)(.*?[%}]})'       : r'\1"\4',
-        }
-
-        for regexp, replacement in unescape_rules.items():
-            subs_made = True
-            while subs_made:
-                xml_text, subs_made = re.subn(regexp, replacement, xml_text)
+        for regexp, replacement in self.escape_map.items():
+            while True:
+                xml_text, substitutions = regexp.subn(replacement, xml_text)
+                if not substitutions:
+                    break
 
         return xml_text