feat(android): adding showcancel property

[akansha-maheshwari]

https://jira.appcelerator.org/browse/MOD-1867

Adding default-overlay.js file to show default cancel behavior.

[build]

	Messages
📖	💾 Here are the artifacts produced: ti.barcode-android-5.0.3.zip ti.barcode-iphone-5.0.0.zip
📖	✅ All tests are passing Nice one! All 146 tests are passing.
📖	🎉 - congrats on your new release

Generated by 🚫 dangerJS against 5379284

[jquick-axway]

@akansha-maheshwari-axway, the files under the following folders were not made by us.

• ./android/src/com/google/zxing/client/android
• ./android/platform/android/res

We copied the above file trees from the open source "zxing" repo below. Note that this open source project does not offer an AAR which means its res files have to be copied over to our project. Also, not all of its source code is provided by the zxing JARs which is why we have to copy the open source project's Java source tree to this repo.
https://github.com/zxing/zxing/tree/master/android

This means the edits you are making to these folders may end up being lost the next time we update this module with the newest zxing changes.