Description
    Base class for handling the import of the spreadsheet file

Atttributes
  schema
  dry_run
    Set to true if this is only a test

  file_name
    The name of the spreadsheet

  import_type
    Three formats are supported, csv, xls, ods

"PRIVATE" ATTRIBUTES
  import_iterator
    An iterator for reading the import file

  warnings
    An arrayref w/ all the warnings picked up during processing

  errors
    An arrayref w/ all the errors picked up during processing

  timestamp
    Time of the import run.

METHODS
  _build_import_type
    Build the import type. It can be either csv, xls or ods.

  _build_import_iterator
    Build the import iterator..

  do_work
    Import a file

  validate
    Validates the import file

  handle_row
    Handle each individual row.

  import_run
    Imports the nodes after validate has been run

  import_transaction
    Called inside the transaction block

  import_failed
    Called if the import failed for some reason

  import_succeeded
    Called after the import has finished succesful

  report
    Make a report of what happened

