Fix: Proguard config to fix build.

[KishoreBabuIN]

Add -dontwarn for rxjava adapters for retrofit 2. Now the repo can build a release build out of the box.

[jemmaSlater]

Hello! Thanks for opening a pull request and sorry for the delay in response.

I agree it would be nice to be able to build a release build out of the box, and your pull request does seem to 'fix' this, however when I check out your changes, although the build is successful, I get 3,376 errors displayed in Android Studio. Do you also see these errors?

This does not seem an ideal situation, and I wonder if there is a better configuration for this file which does not produce any errors or warnings. I've only been able to spend a small amount of time looking into this, and have yet to find a good solution. It does seem like the proguard file needs revisiting, for example: it contains rules for the Otto library which is no longer used within the boilerplate project.

Unfortunately our studio is now closed until the new year, but I will try to find a solution when we re-open. Feel free to make any changes in the meantime. Happy holidays! :)

[ribotaccounts]

Can one of the admins verify this patch?