ENH: Deprecate ::Zero and ::One

These were deprecated in 2012; just before the ITK 4.2 release.
ZeroValue() and OneValue() should be used instead.

vim $(git grep -l "::Zero\>")
:%s/::Zero\>/::ZeroValue()/g

vim $(git grep -l "::One\>")
:%s/::One\>/::OneValue()/g
STYLE: rm explicit void for parameterless function

Functions that take no parameters do not need an
explicit void designation.  Removing these unnecessary
designations provides more consistent code style and
allows for easier regular expression code
maintenance.

%s/( *void *) *const *;/() const;/g
%s/( *void *) *;/();/g
Merge pull request #141 from stnava/StyleChangesForFuture

Style changes for future