Add class when alertify-logs is empty

[johnsardine]

The design I applied to the log list, contains paddings and it appears even when the log list is empty, I think i would be usefull to add a class for when the list is empty so that people can hide the log list and show when needed. Thank you

[fabien-d]

Never considered that use case. An extra class would be a viable option.

A quick workaround, until a solution for all targeted browsers is available, is to use the :empty CSS selector (browser support).

.alertify-logs:empty {
    display: none;
}

[fabien-d]

Fixed with ^ pull request. Will be part of release 0.4.0

[fabien-d]

Moved to 0.3.5 release