Update README.md

Minor Nit. Happy 2018 IO

Change to a better focus mode for modern devices. Good luck, IO 2018ers.

Minor edits before IO 2018.

Removing the Play Services from the start of the Codelab.

Minor updates for IO 2018. Happy Codelabbing, all.

Merge pull request #267 from AdamSHurwitz/master

Adding ability to consume barcodes in BarcodeCaptureAcitivity by adding interface too BarcodeGraphicTracker

Update the gradle ersions and buildToolsVersions of the codelabs to match the IO 2017 Kiosk images.

Merge pull request #179 from googlesamples/fix-ocr-app-id

Update build.gradle

Merge pull request #172 from bhargavms/patch-1

Removed incorrect indentation

Merge pull request #170 from googlesamples/permission-fix

Fix zoom gesture crash; request camera permission upon tap if not granted.