Use AndroidExecutors on Android

* Fallback to java.util.concurrent.Executors on JVM
* Publicize bolts.android.AndroidExecutors
* Create BoltsExecutors
Merge pull request #23 from BoltsFramework/grantland.java

Update to allow usage on Android and JVM
Hide AndroidExecutors and BoltsExecutors
Merge pull request #28 from BoltsFramework/grantland.private

Hide AndroidExecutors and BoltsExecutors
Rename artifact to com.parse.bolts:bolts-android

Also sets Bundle-Version and Bundle-Name in MANIFEST.MF for .jar
and bolts.BuildConfig#VERSION_CODE in .aar
Merge pull request #29 from BoltsFramework/grantland.pom

Rename artifact to com.parse.bolts:bolts-android
Fix POM

Failed POM validation: requires developer information
Release 1.1.1
Prepare for next development iteration
Add shields