Check whether context item is an array before using it.
Check whether context item is an array before using it.

Fixes #24. This will be necessary once implicit iterators make it into production. It will also save people from themselves if they put an iterable array where Mustache expects to find a context.
BrunoDeBarros/mustache.php,bobthecow/mustache.php,sophatvathana/mustache.php,cgvarela/mustache.php,ericariyanto/mustache.php,zuluf/mustache.php,thecocce/mustache.php,irontec/mustache,evdevgit/mustache.php