Issue

Currently *org.bson.json.JsonReader *in unable to read all base64 characters when creating BinData
Troublesome characters:* '+', '/', '='*

This makes for example org.bson.Document.parse(final String json) fail when reading documents with binary uuids.

To reproduce:

*in org.bson.json.JsonReaderTest.testBinDataWithNew() *
replace
`String json = "

{ \"a\" : new BinData(3, AQID) }

";`

with
`String json = "

{ \"a\" : new BinData(3, AQIDBA==) }

";`

to get new byte[]

{1, 2, 3, 4}

it will fail as BinDataConstructor expects only unquotted string as byte value and
org.bson.json.JsonScanner.scanUnquotedString()
reads only '$', '_', letters and digits