Recognize Java versions greater than 1.8

[geoffreyharding]

Fix errors when using QueryDSL with JDK version 9 or higher.
Example error : "parameterized types are only available if source level is 1.5 or greater"
Root cause: codegen does not recognize the new Java versioning scheme (JDK 8: "1.8", JDK 9: "9").
Perhaps there exists a better fix but for our purposes this was the simplest workaround.

[Shredder121]

Oh, it looks like Travis doesn't do Java 7 anymore.
But at least as a stopgap solution this might work.
Let me think about this.
I already think that if the version parsed as double/int/whatever is higher than 10, it's a new version scheme.
But if this has repercussions I do not know yet.