Upgrade code source and target to Java 1.8
Upgrade code source and target to Java 1.8

Without code refactoring.

JeanRev/TeamcityDockerCloudPlugin,JeanRev/TeamcityDockerCloudPlugin,JeanRev/TeamcityDockerCloudPlugin,JeanRev/TeamcityDockerCloudPlugin,JeanRev/TeamcityDockerCloudPlugin