jspm bundle failures does not fail build

[maxwellpeterson-wf]

A smithy build of a wGulp project can pass successfully even if the bundle step (using jspm bundle) fails.

Example: https://ci.webfilings.com/build/141224

[guybedford-wf]

I've added a fix in jspm/jspm-cli@a7826d1 to ensure an error code is returned for failed bundles like failed installs.

Also running jspm through the API would allow error detection as well.

[maxwellpeterson-wf]

Thanks! Ah yes - I should look at running it through the API instead.