Added SerialsReceivingHisRec class, which is mapped to "issues" exported
from Sirsi.  

The code to map the serials and issues data in the olemigration database
to serials receiving and serials receiving history records in OLE is
complete and is now called in LU_DBLoadInstances.

ISBN's (the 020 field in a Marc record) are now modified to be valid
before bib records are inserted into the database.

Several changes to tables and fields in docstore classes to reflect new
database schema.  CallNumberType's now map to ole_cat_shvlg_schm_t
rather than ole_ds_callnumber_type_t.  ExtentOfOwnershipType is now
mapped to ole_cat_type_ownership_t, since ole_ds_ext_ownership_type_t is
now gone.  The Item class now contains a Deliver_ItemType and
Deliver_ItemStatus directly as its itemType and itemStatus, rather than
the intermediary ItemType and ItemStatus classes which mapped to
ole_ds_item_type_t and ole_ds_item_status_t and contained the
Deliver_ItemType and Deliver_ItemStatus instances.  ReceiptStatuses are
now stored in ole_cat_rcpt_stat_t, and ole_ds_receipt_status_t is gone.