[dataimport] remove _rql heresy
1) ObjectStore knows nothing about rql, it just drops it on the floor
2) RQLObjectStore has a session, it can run rql that way
3) setting an object's "_rql" attribute is not a reasonable user-facing
interface
Also drop _commit attribute from base ObjectStore, it doesn't use it.
Schema of the data
------------------
First take a look at the data schema_ then try to remember that you are browsing
through a heap of data by applying stylesheets to the results of queries. This
site is not a content management system with items placed in folders. It is an
interface to a database which applies a view to retreived data.
.. _schema: schema