Uploading files to Document Libraries using the REST API

You just use an HTTP PUT to place a file in a library. It's not so much REST as good old HTTP ...

From that link:

WebResponse response = null;

try
{
    // Create a PUT Web request to upload the file.
    WebRequest request = WebRequest.Create(SharePointPath);

    request.Credentials = CredentialCache.DefaultCredentials;
    request.Method = "PUT";

    // Allocate a 1 KB buffer to transfer the file contents.
    // You can adjust the buffer size as needed, depending on
    // the number and size of files being uploaded.
    byte[] buffer = new byte[1024];

    // Write the contents of the local file to the
    // request stream.
    using (Stream stream = request.GetRequestStream())
    using (FileStream fsWorkbook = File.Open(UploadedFilePath,
        FileMode.Open, FileAccess.Read))
    {
        int i = fsWorkbook.Read(buffer, 0, buffer.Length);

        while (i > 0)
        {
            stream.Write(buffer, 0, i);
            i = fsWorkbook.Read(buffer, 0, buffer.Length);
        }
    }

    // Make the PUT request.
    response = request.GetResponse();
}
catch (Exception ex)
{
    throw ex;
}
finally
{
    response.Close();
}

To update them, then make REST calls subsequently. I've not found a way of doing this that isn't two stage.