* 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).