Remove HTML/XML special entities

By default, libpurple escapes HTML/XML special characters such as double
quotes (resulting in "&quot;" being sent). Avoid this by converting
these sequences back to the original characters.

Signed-off-by: Lukas Fleischer <info@cryptocrack.de>
Merge pull request #40 from cryptocrack/remove-xml-special-entities

Remove HTML/XML special entities