update to Java 8

build with Java 8
added Java8-specific types to DefaultDecoder

v2.0.6: Merge pull request #421 from twicksell/testConfigRulePolish

Refactoring of the Archaius2 Junit Rule.

v2.0.0-rc.25: Merge pull request #334 from elandau/2.x

Seed layers only after application.properties is loaded

v2.0.0-rc.14: Merge pull request #313 from elandau/2.x

Support for DynamicPropertyFactory backed by archaius2