* Tests/gui/NSImage/basic.m: Add basic tests for NSImage.
        * Tests/gui/NSCell/basic.m: Extend basic tests for NSCell.
        * Source/NSImage.m: Try to correct keyed encoding/decoding. Add
        incomplete isEqual: method.


git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/gui/trunk@36384 72102866-910b-0410-8b05-ffd578937521