Smiley API

[Jorge Villaseñor]

Hi, I'm the one working on #1187 I'm on vacations so I will start
working on it again but now with Mauro's help.

We was talking and we have some questions to you
1) The custom emoticons should be managed per-account, per-service or
per-profile?
We think that the better way to manage it is per-service or
per-profile but since purple is based on a per-account way....

2) As we have read the patch, we find that it's to big and adds a
complete feature so, it make sense to add a Smiley API in a
libpurple/smiley.[ch] and use it.
Actually the smileys are associated to an account being added a glist
to the PurpleAccount structure, but may be it's better to have the
smileys independent to the accounts and only at the end link the
account (depending on the answer to 1)

What do you think?