[Feature Request] clear spinner on input change

[krechtern]

** Current behaviour
If a button with [ladda] is clicked, a spinner will be initialized and stored for later use. But if for example the color is dynamic [attr.data-spinner.color]="dynamicColor", the new color is not used because no new spinner will be created.

** Expected behaviour
If the input for example the color changes, the old spinner object should be destroyed. This will result in creating a new spinner if the button is clicked.