Parsing of trailing data

[j-moeller]

Describe the bug
jsoncpp parses trailing commas and ignores trailing garbage which is (technically) not in accordance with the JSON grammar.

To Reproduce
We created a minimum working sample here.

Expected behavior
jsoncpp should abort parsing when encountering a trailing comma or when (trailing) input is left after the parsing attempt.

[daudrain]

@j-moeller,

by default, CharReaderBuilder accepts trailing comma.
You may consider invoking char_reader_builder.strictMode(&char_reader_builder.settings_) to disable this behavior.