Parse smileys in the passed message.
The smiley parsing function which makes pretty faces appear :).
If custom smiley sets are turned off by smiley_enable, the default set of smileys will be used.
These are specifically not parsed in code tags [url=mailto:Dad@blah.com]
Caches the smileys from the database or array in memory.
Doesn't return anything, but rather modifies message directly.