Latest code generated from xmldsig schema

prior commit was inconsistent with binding.xjb
Moved xjc task from build.xml to build.gradle.

Moved schemas to src/main/resources.
Moved to JAXB2 Basics Plugins over JAXB RI XJC task

No appreciable difference to generated code.
Added Equals plugin so that equals() methods are generated
Fixed build.gradle so that everything now compiles

Generated and main classes now get compiled together
hashCode() methods now generated via XJC plugin
Regenerated code using simple binding mode XJC extension

This mode gets rid of a lot of singleton types in the generated code,
greatly simplifying it.
added unit test and other helper code in src/main/java