Add writeU16At(value, position), which is shorter than save()/jump(position)/writeU16(value)/restore(). 
Add writeU16At(value, position), which is shorter than
save()/jump(position)/writeU16(value)/restore(). 


git-svn-id: fcb33a7ee5ec38b96370833547f088a4e742b712@1640 c76caeb1-94fd-44dd-870f-0c9d92034fc1

justinsb/dnsjava