Correct Licensing

[Rovak]

Make sure that the license is correct and compatible with the java-tron project

Update the license headers for the files which are imported from other projects.

Projects

• https://github.com/ethereum/ethereumj/tree/develop/ethereumj-core/src/main/java/org/ethereum
• https://github.com/bitcoinj/bitcoinj/tree/master/core/src/main/java/org/bitcoinj