Report error location when parsing invalid firebase.json file.

[tamalsaha]

fyi: @drtriumph @tomlarkworthy

[coveralls]

Coverage remained the same at 5.54% when pulling 799dc73 on tml-json-ln into b496ec7 on master.

[coveralls]

Coverage remained the same at 5.54% when pulling 5cb741c on tml-json-ln into b496ec7 on master.

[jwngr]

Hot potato. Sending this over to Chris to review.

[cbraynor]

Waiting for testing on all the platforms and converting char location to line/char location

[coveralls]

Coverage remained the same at 5.52% when pulling 0221b13 on tml-json-ln into f093986 on master.

[tamalsaha]

@drtriumph This pull request has been tested on all 3 platforms.

[coveralls]

Coverage decreased (-0.01%) to 5.51% when pulling d67501e on tml-json-ln into f093986 on master.