Write out token value, not internal type

[blgm]

Fixes #73

The S0202 message currently reports the internal token type, rather than the token value. For some tokens that's ok (because they are the same), but for name and literal tokens at least, it's better for the user to see the values that they typed, rather than the confusing (name) and (literal).

[coveralls]

Coverage remained the same at 100.0% when pulling 74e786b on blgm:fixparsemessage into 20e0494 on jsonata-js:master.

[andrew-coleman]

Thank you!