Fix lint npm script to match all files including in src/

[forty]

Description

The current lint rule misses most of the interesting lint errors (in src/) :)

[forty]

Note that this increases the number of lint errors from 177 to 252

[cjbarth]

Thanks for doing this. BTW, did you test this on Windows? I feel like you might need to replace ' with \" to get this to work on Windows and *nix.

[forty]

@cjbarth I don't have a Windows to try that, and I have not idea how quotes work there, so I simply followed your suggestion. It seems consistent with the lint-watch script, so that's at least an improvement.