#49 Improve PackageScanner & ServiceScanner

- better fluent API - ServiceScanner - support for protected/private services - more flexible resolvers - constructors with arguments - factory methods - builder methods - support for priority (annotation?) - support for runtime conditionals/configuration - using another annotations - using builder methods - PackageScanner: application mode - detect JAR by extracting classpath from - PackageScanner.class - passed user class - detected caller classes - scan whole JAR, not only specified root packages - cache result in a file or `java.util.prefs.Preferences` (store both path & timestamp of jar)