Update gradle version to 2.2.3

[doomers]

Update Gradle version from 2.1.2 to 2.2.3 to make instant run faster

shall I send a PR for this?

[opticod]

Along with that, upgrade all dependencies and make sure Travis-ci supports it.

[tanvidadu]

Has PR been sent for it ? I will like to work on it.

[opticod]

@tanvidadu, you can work on it, update all to latest versions and make sure Travis doesn't breaks.

[tanvidadu]

I was sent a PR for the above issue and upgraded it to 3.0.1. There are some license issues in Travis.
You have not accepted the license agreements of the following SDK components:
[Android SDK Build-Tools 26.0.2].

[opticod]

Ok, I will fix that issue of travis. Please direct your PRs to 'bug-fixes' branch.