The tilde (~) character appears incorrectly serialized

[yv13]

To illustrate with a test case:

var o = new HashMap<String,Object>();
o.put("tilde", "~");
assertEquals("{\"tilde\":\"~\"}", JsonStream.serialize(new Config.Builder().escapeUnicode(false).build(), o));

org.junit.ComparisonFailure: 
Expected :{"tilde":"~"}
Actual   :{"tilde":"��"}

[gokce-nur00]

Is is still open?