DbxRawClientV2: For JSON in HTTP headers, escape 0x7F and all non-ASCII characters.
DbxRawClientV2: For JSON in HTTP headers, escape 0x7F and all non-ASCII characters.

I don't think anybody is currently affected by this fix.
- The non-ASCII escaping isn't necessary (things still work without it),
  but it's recommended by the new HTTP 1.1 spec (RFC 7230).
- The 0x7F escaping is necessary to comply with the HTTP spec, but it
  looks like the Dropbox server accepts 0x7F without complaint (which
  I believe is incorrect behavior).

dropbox/dropbox-sdk-java,dropbox/dropbox-sdk-java,dropbox/dropbox-sdk-java,dropbox/dropbox-sdk-java