ParseObject.update/ParseInstallation.create/ParseSession.installationId

[hellokidder]

hi,brother!
Here are some changes I made.

• Add a header to the ParseObject.update and ParseInstallation.create
  It's fix some bug about when I use them,return "request body is empty"

Actually:For POST and PUT requests, the request body must be JSON, with the Content-Type header set to application/json.,but I don't know much about this.I am worried that if I change all of them, there will be some errors that I don't understand, so I only changed the method I am currently using.

• ParseSession add set installationId
  so now:

final ParseSession parseSession = ParseSession();
    var res = await parseSession.getCurrentSessionFromServer();
    if (res.success) {
      final ParseInstallation installation =
          await ParseInstallation.currentInstallation();
      parseSession.installationId = installation.installationId;
      parseSession.save();
    } else {
      print(res.error);
    }

look forward to your reply,hava a good day!

[phillwiggins]

Hey

I think this looks logical. I can't see anything that doesn't look out of place.

Great work! I really appreciate your contributions!