Update Croppa.php
Update Croppa.php

Now we can pass ```$src``` parameter without first trailing slash.
For example, ```Croppa::url('someimageonpublicdir.png', 200);```
arturock/croppa,eXolnet/croppa,arturock/croppa,BKWLD/croppa,BKWLD/croppa,eXolnet/croppa