JAXB-973: generated code should be compilable with '-Xdoclint:all'

Signed-off-by: Petros Splinakis <petros.splinakis@oracle.com>
Merge branch 'JAXB-973' into 'master'

JAXB-973: generated code should be compilable with '-Xdoclint:all'

@martin.grebac @lukas.jungmann
Issue: Code generated by xjc tool fails when generating javadoc under JDK8.
Resolution: Added HTML escape for '>' character in JavadocEscapeWriter.