Show errors if unable to parse /bowerrc

[yosuke-furukawa]

If .bowerrc has some parse errors, bower would output errors to be better.

eg: my .bowerrc like this

{
  "directory" : "bower_dir", //  last comma is mistaken.
}

then, i execute bower install.

$ bower install jquery

But, bower process exits without any messages.

I fixed this issues, if it is acceptable, i will send PR.

https://github.com/yosuke-furukawa/bower/compare/fix;output_error_when_json_err

[satazor]

Bower has this check with a friendly error message, see: https://github.com/bower/bower/blob/master/lib/core/config.js#L60

The problem is that tmp module was swallowing uncaught exceptions.
This was fixed in tmp@0.0.20.

[yosuke-furukawa]

I can see an error in my console. Thanks for your changes!