ENH: Initial adaptive cosmo reader.

This commit adds the initial adaptive cosmo reader
(by courtesy of Jon Woodring) that used the older
streaming framework.
COMP: vtkAdaptiveOptions does not exist anymore

Remove references to vtkAdaptiveOptions, which no longer exists.
ENH: Added vtkACosmoReader to the build
ENH: Add AdaptiveCosmoReader accesible to the UI
ENH: Selection of tagsize(32 or 64-bit) in the UI
ENH: Add Level ivar both in UI + class definition.
ENH: Minor touchups

This commit removes some unused forward declarations of VTK
classes and updates the constructor to initialize all ivars.
ENH: Remove old ivars.

Remove older ivars that were used with the older streaming framework.
STYLE: Define TAG_SIZE_32_BIT & TAG_SIZE_64_BIT
ENH: Added method to extract info from filename.
ENH: Added functionality to load the metadata
ENH: Implement SetupBlockRequest()

Implemented method to setup a block request. If
a downstream filter or sink requests a specific
set of blocks via UPDATE_COMPOSITE_INDICES, this
will be the set of blocks that will be loaded.
Otherwise, **only** the blocks of the requested
level will be loaded.
ENH: Change vtkACosmoReader to output multi-block
ENH: Implement RequestData()
ENH: Store IndexWithinLevel in metadata
ENH: Added method to compute block offsets in file
ENH: Implemented ReadBlockFromFile
DEBUG: added some debuging statements
BUGFIX: Correct GetBlockIndex
ENH: Disable debugging by default