Fix serialization documentation:
Fix serialization documentation:

- Missing dates in XML format
- Missing FFs in JSON format

zaccharles/nodatime,jskeet/nodatime,jskeet/nodatime,zaccharles/nodatime,nodatime/nodatime,nodatime/nodatime,zaccharles/nodatime,malcolmr/nodatime,BenJenkinson/nodatime,zaccharles/nodatime,zaccharles/nodatime,malcolmr/nodatime,BenJenkinson/nodatime,malcolmr/nodatime,malcolmr/nodatime,zaccharles/nodatime