[OpenJDK 2D-Dev] RFR: 8148628: TIFFDirectory(getAsMetaData) created with one TIFFField having a IFD pointer tag throws ClassCastException & other naming differences (JEP 262)

[Brian Burkhalter]

Please review at your convenience.

Issue:	https://bugs.openjdk.java.net/browse/JDK-8148628
Patch:	http://cr.openjdk.java.net/~bpb/8148628/webrev.00/

Summary:
1) Needed to fix some problems in TIFFDirectory and TIFFFieldNode with respect to the fact that a TIFFDirectory contained in a TIFFField may be either the ‘dir’ field or the ‘data’ field.
2) Trivial changes to names in Exif and GeoTIFF tags to better align with the respective specifications.

Thanks,

Brian