Fix dialog renderer
The recent change to remove Pystache introduced a bug in cases where
the passed-in key/value data included non-strings for the value.  This
showed up in the weather skill which passed in "lat" and "lon" as floats.
Now the value is explicitly converted using str().
@@ -76,7 +76,7 @@ class MustacheDialogRenderer(object):
index %= len(template_functions)
line = template_functions[index]
for k, v in context.items():
- line = line.replace('{{' + k + '}}', v)
+ line = line.replace('{{' + k + '}}', str(v))
return line
