Reformat Elm build errors for compatibility with Sublime Text error navigation

[sentience]

Recent updates to Sublime Text 3 have introduced the display of error “phantoms” (dismissible one-line error summaries displayed inline at the source of the error). These, as well as the editor’s next/previous error navigation with (Shift-)F4 were incompatible with the multi-line error pattern matching that was previously used.

This new error formatting includes all required information for the display of error “phantoms” on a single line, which brings the above broken features back to life.

Fixes #4

[scottcorgan]

Looks like syntax highlighting in the build output is broken:

Your PR

Master

[sentience]

Did you run that build after checking out my branch? My PR changes the output format and the updated syntax highlighting depends on that updated format.

[sentience]

Ping! Hoping someone can review this.