MetaIO: Factor duplicate build/install config into one programmable interface
MetaIO: Factor duplicate build/install config into one programmable interface

Recognize parent project unambiguously using METAIO_FOR_[IV]TK.  Both VTK and
ITK now set one of these before using add_subdirectory to build MetaIO.
Refactor the duplicate build properties and install rules for VTK and ITK into
a single implementation programmed by setting variables ahead of time for each
parent project.

SVN-Revision: 3536
tjcorona/MetaIO,opoplawski/MetaIO,opoplawski/MetaIO,tjcorona/MetaIO