Declares dependencies more explicit

[quandor]

• Guava is declared explicitly as a dependency since it is directly used by the projects.
• Some build files no longer emit warnings
• The (hopefully) last dependency version is moved to gradle.properties
• third party license file is up to date

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This change is 

[heiko-holz]

Reviewed 6 of 6 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @quandor)