force_escape should work in iolists.

Fixes #70.

src/erlydtl_filters.erl

@@ -917,6 +917,8 @@ escape("\"" ++ Rest, Acc) ->
     escape(Rest, lists:reverse(""", Acc));
 escape("'" ++ Rest, Acc) ->
     escape(Rest, lists:reverse("'", Acc));
+escape([S | Rest], Acc) when is_list(S); is_binary(S)->
+    escape(Rest, [force_escape(S) | Acc]);
 escape([C | Rest], Acc) ->
     escape(Rest, [C | Acc]).
 

tests/src/erlydtl_unittests.erl

@@ -480,6 +480,12 @@ tests() ->
 		  {"|force_escape",
 		   <<"{{ var1|force_escape }}">>, [{var1, "Ben & Jerry's <=> \"The World's Best Ice Cream\""}],
 		   <<"Ben &amp; Jerry&#039;s &lt;=&gt; &quot;The World&#039;s Best Ice Cream&quot;">>},
+		  {"iolist |force_escape",
+		   <<"{{ var1|force_escape }}">>, [{var1, ["'a'"]}],
+		   <<"&#039;a&#039;">>},
+		  {"nested iolist |force_escape",
+		   <<"{{ var1|force_escape }}">>, [{var1, ["a'", <<"b">>, [<<"<c">>, "d", ["e>"]]]}],
+		   <<"a&#039;b&lt;cde&gt;">>},
 		  {"|format_integer",
 		   <<"{{ var1|format_integer }}">>, [{var1, 28}], <<"28">>},
 		  {"|format_number 1",