Metadata: add value based equals() and hashCode()
Metadata: update javadoc
logging: add raw XML request and response logging

The JVM argument 'ifmapj.xml.log=true' enables raw XML logging.

Fixes #1.
AccessRequest: remove deprecation of administrative-domain
add ifmap-timestamp-fraction to Metadata interface
timestamp-fraction: fix error in javadoc
update version to 2.2.0