Fix #672 - handle invalid UTF input more gently

[wilzbach]

I'm not so sure about this. It will create a lot of overhead :/

[aliak00]

Could an option be to handle it lazily? I.e. wrap in try/catch and do the decoding only if there's an exception?

Or writefln it? (since it seems like writeln deals with this?)

[wilzbach]

I.e. wrap in try/catch and do the decoding only if there's an exception?

Yeah that does sound like the reasonable thing to do. 👍

[wilzbach]

core.exception.AssertError@source/rest/apiv1.d(255): unittest failure
----------------
??:? _d_unittestp [0xdb1f6d]

Urgh that passes on my local machine (added debug output)