Fix #87 - Migrate to Gradle build process and Android Studio, with the
native file structure for new projects in the current version of Android
Studio.  Remove ActionBarSherlock project from the repo, as well as the
/libs commons-io and Jackson .jar files, in favor of remote artifacts
managed via Gradle.  Update Readme with new build instructions.
Update readme with more troubleshooting info, fix a few typos.
More readme clarifications.
Update to #88 - Add copyright header.
Remove .idea and iml files

These have local configuration paths that shouldn't be in source
control. They are created automatically when importing into Android
Studio according to the README.
Add .idea to .gitignore

And iml files
Mark gradlew as executable
Enable release builds

This adds support for adding a secure.properties file. I'm not sure if
I exactly like this, because I'm not sure if we're supposed to ignore
the gradle.properties file. But I can't figure out how else to specify
the secure properties.
Bump version, update What's New

The biggest what's new is the updated build system, but no one cares
about that....