`TokenBuffer` defaults for parser/stream-read features neither passed from parser nor use real defaults

[cowtowncoder]

It looks like TokenBuffer explicitly passes 0 for "parser feature flags" from its constructor. This is wrong; it should either:

• Ideally pass flags of JsonParser it is constructed with (if any), OR
• Defaults combined from features in question (same as what JsonParser defaults to)

At first it is probably necessary to just do latter.

[cowtowncoder]

Fix for 2.x simply sets parser/stream-read features to defaults; no way to (yet) pass real values from parser being buffered.

3.x could likely work better but I might not have time to tackle that yet; should be no worse than 2.x for time being.

[cowtowncoder]

3.x may already work better, but no tests to verify. Should, in general, test combination of Feature settings, overrides, better for 3.0 since it is capable of more accurately handling things.

But for now this has to do.