Document!!!!!


VDC2
----

HIGH

Currently no verification that .vdf file agrees with what is
in .ncdf files

User Documentation

MEDIUM

construtor without metadata

vdfcreate should automatically compute compression ratios based on bs and
wavelet 

Constructor when not metafile is available.

IDL interface

LOW

Add VDC2 support to Layered data reader


WaveCodeIO/Compressor need to be able to handle volumes with extreme aspect
ratios  (e.g. a volume 1000x1000x4 will not be compressible with because the 
4 dimension will limit the 3d transform).

Get rid of MetadataSpherical specialization (or figure out how add
support to it for vdc2)



Test:
 + odd and non-symmetric block size
 + Read vdc1 file
 + writing and reading regions with wholes (incomplete regions)
 + verify reading/writing subregions

Alan:

+ VariableExist and GetRegion has lod parameter
+ block size varies with level
+ killed many reference return types
+ Changes to SetVariableNames (deprecated), impact on scripts
+ GetVDCType()


Doc:

+ Compression ratios specified apply to 3D data. 2D compression ratios
are derived from 3D (see WaveCodeIO constructor)
