added simple test (todo) for capturing and returning errors from TSC
Catch `tsc` errors

  - Fixing issue https://github.com/UCSD-PL/RefScript/issues/8

  - tsc's output when the --refscript flag is given is a JSON
    representation of `FixResult Error`
Merge pull request #9 from UCSD-PL/tsc_errors

Tsc errors