Add comment support in JSON (jsonc)

[wait-what]

Closes #94. This PR adds comment support in the JSON parser. Comments are now ignored instead of causing an error. This should have no effect on valid JSON and adds virtually no overhead.

{
    "a": "b" // inline
    // single line
    /* multi
         line */
}

I have added 4 relevant tests and would appreciate if someone would test some more edge cases I didn't think of.

[knickish]

@not-fl3 Are you aware of any issues this might cause?

[knickish]

gonna just go ahead an merge it then

[not-fl3]

Oh, sorry, I missed this PR, sure, I don't see any issues :)