installation: fix for table drops and upgrades

* Fixes dropping of "goto" table in case of destroying site
  records or the entire site.

* Fixes loading of "citation errors" table and "goto" upgrade
  recipes to mark them as done when installing Invenio for the
  first time.
BibDocFile: new document data model

* New document data model allowing for more flexible data storage.

* Allows to have standalone documents not attached to records.

* Allows to store "more info" dictionaries about documents in more
  flexible manner.

* Enables relation between documents and particular versions.

* Provides new BibUpload extensions (BDM, BDR) allowing to manipulate
  all important data structures.

* After installing this commit on an exiting database, the upgrade
  procedure is executed.  (Can be lengthy depending on the number
  of records.)

* Merge note: checked tabcreate and upgrade statements and modified them
  so that they would lead to exactly identical results.  Files touched:
    modules/miscutil/lib/upgrades/invenio_2012_11_15_bibdocfile_model.py
    modules/miscutil/sql/tabcreate.sql

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
Merge branch 'master' into next

* master:
  BibDocFile: new document data model
  installation: fix for table drops and upgrades