STYLE: Remove entries from the old MINC2ImageIO.

It has now been removed.

Change-Id: I8b7125ea868e067c65aae99954c02c66a2d95f03
BUG: Remove MINCIO from the default registered modules.

ExampleIOPluginTest is fixed by calling
ObjectFactoryBase::RegisterFactoryInternal.

ITKIOMINC is also marked as EXCLUDE_FROM_ALL per previous discussion,
so it can go through more testing like the DCMTKIO module before being
built by default.

Change-Id: I10150a8615f99b5c12b02bf3a8931d849e1d2a17
Merge topic 'MINCDangles'

8a86d3c BUG: Remove MINCIO from the default registered modules.
074569a STYLE: Remove entries from the old MINC2ImageIO.