Added script to generate solrdump for xworks dump.

xworks dump is denormalized works dump structured differently. The
generate_deworks.py script is modified to produce the new format.

Added a script `solrdump.py` that takes the xworks dump and produces the
solr dump. Currently it produces dump of only edition types.

Also added a script to generate OL dump in the dev-instance.
Added work documents to solr dump.

In update_work.py, separated the code to fetch data and code process it.
This allowed us to call the processing code from solrdump.

Also, fixed a bug in generate_deworks.py, that had a typo in specifying ia_metadata.
Replaced all prints with logging.

Required to avoid interference with solrdump.
Delete entries from Solr when a work is deleted.