* Priority optional unchanged:

  * sisu
  * sisu-pdf, extra depends on: ttf-liberation, resolve issue later,
    if necessary use another font
  * sisu-postgresql, extra depends on libdbi-ruby1.9.1 & libdbd-pg-ruby1.9.1
  * sisu-sqlite, extra depends on libdbi-ruby1.9.1, libsqlite3-ruby1.9.1 &
    libdbd-sqlite3-ruby1.9.1
  * sisu-complete, extra depends on: sisu-postgresql & sisu-sqlite

* seek to persuade that ruby db drivers should be optional to match ruby and the
  databases (postgresql & sqlite); else developers using priority optional
  database and priority optional ruby by the use of ruby drivers to access
  database are obliged to develop for priority extra, seek a fix (so as to
  remove this suboptimal default predicament).