Minor change: renamed indexed dataset output files in 19_query.sh for ALACRITY to always have the sigbits in the filename
Fixed PG dimensions in build_indexed_dataset for DS-particle
Bugfix: fixed unexpected behavior in inq_var_blockinfo in read_bp.c: when requesting 'pre-transform' dimensions, an assertion trips if the variable is not actually transformed. A better response (now implemented) is to simply return the original dimensions anyway, since this is what is expected, since 'pre-transform dimensions' really means 'dimensions originally specified by the user'.
Factored out common functionality from the identity transform for reading from original data embedded in transformed data (will be used by ALACRITY to handle normal reads by forwarding them to a copy of the original data stored after the index in transformed blocks)
Made transform_metadata and transform_metadata_len available to transform plugins during reads via the pg_read_requests struct
Added original-data mode to ALACRITY transform in addition to LOB-only mode when reading
Merge branch 'alacrity-orig-data-final' into adios-query

Integrated ALACRITY Transform plugin updates to support storing the original data
*and/or* low-order-bytes-encoded-data alongside the ALACRITY index, rather than
previously low-order-bytes-encoded-data being the only option.

Additionally, introduces a refactored Identity plugin that can provide its
original-data-reading services to other plugins via factored-out common
functionality.

Also fixes a few minor bugs/limitations of the Transform framework in general: adios_pg_read_request
structs now provide the plugin-specific metadata for each specific varblock, and fixed an overzealous
assertion in read_bp.c.