Add spec for changing delimiters (issue #77)

spec/_files/changing_delimiters.js

@@ -0,0 +1,4 @@
+var changing_delimiters = {
+  "foo": "foooooooooooooo",
+  "bar":"<b>bar!</b>"
+};

spec/_files/changing_delimiters.mustache

@@ -0,0 +1 @@
+{{=<% %>=}}<% foo %> {{foo}} <%{bar}%> {{{bar}}}

spec/_files/changing_delimiters.txt

@@ -0,0 +1 @@
+foooooooooooooo {{foo}} <b>bar!</b> {{{bar}}}