refactor(parse-all): report error per parser

[petergoes]

When a parser errors, report what happend to the user. Continue with all parsers before exiting. Parsers are started in paralell, we need to wait for all of them to complete to clean up the temp folder.

[petergoes]

70

[jpsc]

Looks good to me :)

[jbmoelker]

as discussed:

• move process.exitCode = 1; to bin/fastatic
• return parse promise after copying to dest so that consuming modules (like bin/fastatic) can hook onto resolve/reject. and use this parse to finish internal cleanup and logging.

[jbmoelker]

@petergoes I propose we revisit this one after you've updated the new stats parser. I think the signature of the main index.js will have to change to return those stats.

[petergoes]

the last commit builds on top of #94

[petergoes]

I just realised, by handeling error reporting I do in the last commit, the module is never going to exit with an exit code. Any error in the parsers is caught, so the catch wil execute, hence, consuming modules will always have to actively check the output to see if there are errors and can't rely on their own catch implementation.

Maybe it's worth to discuss this in person?

[petergoes]

Closing this PR and putting the error reporting in another branch based on #94