BUG: Put ImageIOBase helper function in anonymous namespace

The WriteBuffer templated helper function in this file is already in an
anonymous namespace, ReadBuffer should be too.

Change-Id: Iac2f5c944209c4433e61a928350f67691ca52c1a
BUG: Make RealTimeClock on Windows report consistent time.

The itkRealTimeClock in Windows tries to convert Windows-time stamps since
1601 to unix time since 1970. It actually does not subtract the time
difference, but adds it again, so that the time is given since 1232.

Change-Id: I6c15259362c8fb8e7516f20e9d49384d0da6d8c7
Suggested-by: Peter Fischer.
Merge topic 'ImageIOBase-Namespce'

4a416c2 BUG: Put ImageIOBase helper function in anonymous namespace
Merge topic 'Windows-Clock'

273c1cb BUG: Make RealTimeClock on Windows report consistent time.