added 2 aliases for X( smiley

>.< and >_<
corrected 2 smileys >.< and >_<

fixed comment issue:
https://github.com/WoltLab/WCF/pull/1608#issuecomment-31148990
this:
<smiley name="&lt;X">
confused me :)
Merge pull request #1608 from FirePanther/smiley.xml-1

added 2 aliases for X( smiley