Adds Apache License Headers, enables rat-check, find-bugs and checkstyle plugins. Contributed by Venkatesh Seetharam

Guice module-loading annotation

they are not services and made more sense with simpler, shorter names

ServiceInitializer and Services collection no longer exist and have been
replaced by Guice dependency injection.
Added comments and improved testability.
Maven verify now runs - almost ready for CI (issues with keytool maven
plugin)

properties file

with integration tests (specifically the metadata.keystore file &
keystore plugin), but int tests are otherwise loading Guice
dependency-injected instances correctly.

file (indexer.properties).