[patch] urlencode filter fails when passed an integer

[Chris Beaven]

My code which is failing:

<a href="...?id={{ user_id|urlescape }}">

user_id is sometimes an integer (when pulled from database), which caused urlescape to fail.

I could just str() it in the view, but it shouldn't really matter. The simple patch converts to a string if it isn't one already.

[Malcolm Tredinnick]

(In [4496]) Fixed #3155 -- Allow an integer to be passed to the urlencode filter. Patch
based on one from SmileyChris.