Apply new glyph-image conventions for some ID-feature-names:

Apply new glyph-image conventions for some ID-feature-names:
- Use `=ucs@unicode', `=adobe-japan1-5', `=jis-x0213-2' and `=gt'
  instead of `=>>>ucs@unicode', `=>>>adobe-japan1-5',
  `=>>>jis-x0213-2' and `=>>>gt' for abstract glyph-images.
- Use `=gt-k' for abstract glyph-images.
- Move `=gt-pj-*' to abstract glyph-images.
- Use `==ucs@unicode', `==adobe-japan1-5', `==jis-x0213-2', `==gt' and
  `==gt-k' instead of `=ucs@unicode', `=adobe-japan1-5',
  `=jis-x0213-2', `=gt' and `=gt-k' for representative glyph-images.