fix(predictions): TABLE, CELL & KEY_VALUE_SET blocks are not properly processed

[ruiguoamz]

Description of changes:
Bug fix according to: #641

• Refactored processText(_ textractTextBlocks: [AWSTextractBlock])

• Fixed the bug where TABLE, CELL blocks are not properly processed

• Fixed the bug where KEY_VALUE_SET blocks are not properly processed

• Updated integration tests

• Update README.md

• Replaced AWSMobileClient with Amplify.Auth

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[wooj2]

1. The employmentapp.png test case comes from here:
   https://github.com/aws-samples/amazon-textract-code-samples/tree/master/src-csharp/test-files
   a. The file is still a png file, so, it should not have a .jpg extension.
   b. I think we should just leave it as employmentapp.png

2. testImageTextWithTables.jpg does not seem to be a good test, because it has the same values in each of the tables.

[wooj2]

Please rename the file testImageTextAll.jpg to employmentapp.jpg. textAll is ambiguous -- for example, the image does not have a celebrity, and does not address all cases that we currently support.

[wooj2]

I don't think you understood my comment -I noticed that there is a call to Amplify.reset() in the two functions:
setUp() and tearDown() -- I do not think it should be in both places. I think it makes sense to have it only in tearDown()

[wooj2]

It looks like we were configuring our integration tests through code (versus a file)... Was there a discussion among the team that we want to adopt this approach? Was there a problem with the approach we had before?

[ruiguoamz]

According to Jithin, there is no specific reason why not using one over the other. Since the other categories use file way of configuring, then I would also adopt that way and it's more convenient.

[wooj2]

Please fix the code with regards to removing the processSelectionElement function. After that, feel free to adopt additional comments, or just push.

Also, you will want to update the Changelog.

[wooj2]

You can revert changes in this file.

[wooj2]

I understand trying to re-use code here, but in this case, I think it actually adds complexity. Lets remove this function.

[wooj2]

Replace with:

                        if (!selectionItemFound) {
                            selectionItemFound = true
                            //TODO: http://www.github.com/aws-amplify/amplify-ios/issues/<fill in issue number here>
                            // Support multiple selection items found in a KeyValueSet
                            isSelected = selectionStatus == .selected
                        } else {
                            Amplify.log.error("Multiple selection items found in KeyValueSet")
                        }

[wooj2]

replace with:

                    if (!selectionItemFound) {
                        selectionItemFound = true
                        //TODO: <link>
                        //Support multiple selection items found in a cell
                        isSelected = selectionStatus == .selected
                    } else {
                        Amplify.log.error("Multiple selection items found in a Cell")
                    }

[wooj2]

If you want to avoid this, you can create a file like:

IdentifyTextResultTransformers+Tables.swift (and similarly with key value)

and then put:

extension IdentifyTextResultTransformers {
    static func processTables(...
    static func processTable(_ tableBlock: AWSText...
    static func constructTableCell(_....
}