Increase JDK baseline from Java 6 to Java 8

Due to fix #21 we need to increase JDK baseline from Java 6 to at least Java 7.
But at this point in time, Java 8 is the oldest supported version so let's just move to it.

Change needs to result in at least minor version bump so let's also move from 1.0.x to 1.1.0 for this project.
