[Lazarus] @DBAware controls users

[Luiz Americo Pereira Camara]

Hi,

I just commited some changes in TFieldDataLink and DBAware Controls like 
TDBEdit and TDBMemo

It fixes some bugs and also avoid some double calls of events

Anyway may be some regressions

Please create bug reports and point here if something that was working 
before broke

Luiz