Include CSDForm, CSDWindow in common.h

For using CSDForm and CSDWindow in all .cpp files, I add including this
headers.
Fix GetSDWindow(...) bug

Dealing with shared memory, WE MUST DON'T USE POINTER because of no
valid pointer on shared memory.
Add reloading sdform file in dll

Now, sync problem within dll has been solved.
Add checking moving cursor onto titlebar

From sdForm, I can check whether moving mouse cursor onto titlebar.