$.addClass for custom class called too late

[jayd3e]

If you define a custom class for your tip, it is applied too late in the process of showing the tip, resulting in weird style bugs. For example, if you have a default stylesheet for tips, where the 'max-width' property is set for all tips, and then you overwrite that property in your custom class. The position of the tip will be calculated based off of the max-width in the default stylesheet, but the tip will actually look as it is defined in your custom class.

[steveluscher]

Fixed in #170.