Fix echo in Windows (issue #2)
Fix echo in Windows (issue #2)

The `echo` command does not work in Windows because `casperjs` needs to be launched with the .cmd extension. This is done correctly in the `test` task but not in `echo`.
tokimari/BackstopJS,mirzazeyrek/BackstopJS,garris/BackstopJS,thepechinator/BackstopJS,tokimari/BackstopJS,garris/BackstopJS,klausbayrhammer/BackstopJS,limptwiglet/BackstopJS,cookchristopher/BackstopJS,mirzazeyrek/BackstopJS,paleite/BackstopJS,paleite/BackstopJS,limptwiglet/BackstopJS,monestereo/BackstopJS,felquis/BackstopJS,pelllich/BackstopJS,cookchristopher/BackstopJS,klausbayrhammer/BackstopJS,garris/BackstopJS,monestereo/BackstopJS,KMK-ONLINE/BackstopJS,felquis/BackstopJS,KMK-ONLINE/BackstopJS,thepechinator/BackstopJS,pelllich/BackstopJS