Fix first slide bug

Fix first slide, #23 , #24

Version 0.1.8

Update: version label 0.1.8
Fix: duplicate elements using ng-if in wrapper element #5
Fix: fade=true with autoplay #6
Fix: on-after-change and on-before-change errors #8
Fix: compatible with angularjs version < 1.4 #9
Fix: slides do not update when the array changes #10
Next and prev button will be visible when set in the options Carousel and directives attributes
Set next and prev button will be visible in the option

Version 0.1.7

Fix: Carousel infinite loop
Fix: the onInit function callback has been called too soon

Version 0.1.4

Compatible with angular 1.6