Official card.io Android release process

This is probably only useful for maintainers.

Make sure you're using NDK r10d! Ndk 8 is broken for some devices.
Sanity check the master branch.
Run ./gradlew clean :card.io:assembleRelease releaseDoc, and review the unobfuscated aar and javadocs for any anomalies.
Deploy release version of SampleApp with ./gradlew installRelease to a device and run a few sanity checks. You will have to generate keystores to do this.
Run git checkout -b release/1.2.3 master with a release version
Update release_notes.md and commit.
Run fab sdk_reset sdk_release, it will reset the branches, build the sdk in the distribution-repo folder, tag the release, and deploy to mavenCentral.

Switch to master and merge release branch

    git checkout master
    git merge --no-ff release/1.2.3

Now push the changes to origin repo
```
    git push origin master --tags
```
Wait for tests to complete and let's release to public, check the diffs to verify all is good
1. Check the changes
```
    cd distribution-repo;
    git show
```
2. Promote the repo in maven central 2. Open Sonatype, and 2. Follow these instructions 2. Only when the card.io maven repo lists this release, proceed to next step. Otherwise, the sample app won't compile.
3. Push
```
    git push public master --tags
```
Update javadocs
1. On public repo, checkout special gh branch called gh-pages: 2. git checkout gh-pages 2. rm -rf `ls | grep -v *.md`
2. On private sdk rep, build javadoc and copy to public repo: 2. ./gradlew releaseDoc 2. cp -a card.io/build/docs/javadoc/release/* <public repo dir>
3. On public repo, push the changes: 2. git push
Check github that all is good.
Post that a new release is available using the same format previously used to:
1. https://github.com/card-io/card.io-Android-SDK/releases
2. Twitter (username=cardio/password=ask for password)
3. Google Groups (send email to card-io-sdk-announce@googlegroups.com)

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