Dali::Vector release data more safe (Dali::Vector::Replace)

Dali::Vector release data more safe (Dali::Vector::Replace)

We got some issue when someone use mData
during Dali::Vector is on reserving.

In this case, mData = nullptr (or mData memory is deleted.) very short time.

Now, we add VectorBase::Replace(void* newData) function.
It mean, VectorBase::mData will be replaced as newData.

It can block thread integrity issue.

Note : VectorBase::Copy can have nullptr between Release() <-> Reserve()
There is no way to fix it without any additional memory.
So just keep current implement logic.

Change-Id: Ie09b1bc00146f4c3be9294853a32c093b3597fba
Signed-off-by: Eunki, Hong <eunkiki.hong@samsung.com>