Consistently use version 2.9.1 of maven-javadoc-plugin.
Build bitcoinj-examples and bitcoinj-tools with Java 8. Bitcoinj-core and orchid still requires Java 6 so it can run on Android.
Wallet-template is now a proper sub-project. This reduces the risk for breaking the wallet-template build.
Configure Travis to compile everything using Java 8, then compile orchid and bitcoinj-core using Java 6.