Updated extensions:
Added onDismiss callback on the Context.dialog functions
fun Context.dialog(@StringRes title: Int, @StringRes message: Int, @StringRes positive: Int?, @StringRes negative: Int?, posAction: (MaterialDialog) -> Unit, negAction: (MaterialDialog) -> Unit, dismissAction: ((MaterialDialog) -> Unit)? = null)
fun Context.dialog(title: String, message: String, positive: String?, negative: String?, posAction: (MaterialDialog) -> Unit, negAction: (MaterialDialog) -> Unit, dismissAction: ((MaterialDialog) -> Unit)? = null)