Should throw some kind of error when DART_SDK is not defined.

[digitalfiz]

Since this package depends on $DART_SDK to be set it should throw an error when its not.

[devoncarew]

Hmm, some of the tasks require locating an SDK; some tasks would not. And we try and locate an SDK even in the absence of the DART_SDK env variable.

Perhaps a utility method would be in order, to throw if a dart SDK can't be located? Scripts would need to call that in their init phase if they depended on tasks that require an SDK.

[digitalfiz]

Sounds good to me :-D

It was frustrating trying to figure out why I was getting errors about path method not found. Actually found the solution on another projects issues tab so I thought I would relay it here.

[devoncarew]

We added support for this in 0.5.7 - tasks which require an sdk now throw if one is not present. Thanks for the report!