Indicate that the build was successful after a build error.

Prior to this change if a build errored it was not possible to know from the console if that issue has been corrected. This forced us to stop && restart the server to get feedback (even though it had likely already been fixed).

This change adds a "Build successful." message when the build had previously errored (the stack was already printed to the screen), and is now built properly.

@danmcclain / @rjackson

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Screenshot:

![screenshot](http://monosnap.com/image/PS53sco0kAgdKwdmgykVoYrRieK4eh.png)