Jing does not build with Java 8

```
mod.rng-parse.compile-main:
[mkdir] Created dir: /home/jostein/daisy-pipeline/pipeline-osgi-libs/jing/target/checkout/build/mod/rng-parse/classes/main
[javac] Compiling 34 source files to /home/jostein/daisy-pipeline/pipeline-osgi-libs/jing/target/checkout/build/mod/rng-parse/classes/main
[javac] warning: [options] bootstrap class path not set in conjunction with -source 1.5
[javac] warning: [options] source value 1.5 is obsolete and will be removed in a future release
[javac] warning: [options] target value 1.5 is obsolete and will be removed in a future release
[javac] warning: [options] To suppress warnings about obsolete options, use -Xlint:-options.
[javac] /home/jostein/daisy-pipeline/pipeline-osgi-libs/jing/target/checkout/build/mod/rng-parse/gensrc/main/com/thaiopensource/relaxng/parse/compact/CompactSyntax.java:1590: error: incompatible types: Annotations cannot be converted to AnnotationsImpl
[javac] a = IncludeBody(include, scope, a);
[javac] ^
[javac] where AnnotationsImpl,Location,ElementAnnotation,CommentListImpl are type-variables:
[javac] AnnotationsImpl extends Annotations declared in class CompactSyntax
[javac] Location extends Object declared in class CompactSyntax
[javac] ElementAnnotation extends Object declared in class CompactSyntax
[javac] CommentListImpl extends CommentList declared in class CompactSyntax
[javac] Note: /home/jostein/daisy-pipeline/pipeline-osgi-libs/jing/target/checkout/build/mod/rng-parse/gensrc/main/com/thaiopensource/relaxng/parse/compact/CompactSyntax.java uses unchecked or unsafe operations.
[javac] Note: Recompile with -Xlint:unchecked for details.
[javac] 1 error
[javac] 4 warnings
```