fix Shield link do not re-link after EMP-ed/Disarmed. Need to deploy VERSION{v1.2.7.5} 

previous optimization accidentally skip update of shieldUnit with NO_LINK (this is an EMP-ed shieldUnit). 

Also, some rename of some functions to reduce messiness and encapsulated some regularly used task. This is on commit no.2 to not mix it with bug fix.