Use system.args if phantom.args is undefined

[nathanvda]

In phantomjs versions > 2.0 phantom.args is
no longer supported, and we should use system.args instead.

When I installed screencap on my dev machine, it just worked, but somehow when deploying on my clients windows server it did not work. I got an error on phantom.args being undefined, and when looking it up, I found it is no longer used in the new versions (>2.0). We should use system.args instead. For me this version works on both my dev machine and windows server.

The code should still work for lower versions as well.

[nathanvda]

From the documentation: http://phantomjs.org/api/phantom/property/args.html

[DEfusion]

Note that this was added also in my open PR #28

[nathanvda]

Hi @DEfusion indeed, but your branch has not yet been merged, so I assumed the rest of your branch was up for discussion, but this should be merged anyhow, so I imagined a "leaner" branch could get merged sooner.

[nofxx]

I confirm this works with phantom 2.1.1 on archlinux!

Please merge!

Thank you!