Process NEW_CLASS_EVENT as exepected
Make sure legacy clients can register events

This allows liboro users like oro-view to subscribe to
events.
The simple RDFS reasoner now correctly classify every models
Teach the reasoner about owl:equivalentClass

Which implicitely means the resoner is now a very incomplete OWL-DL reasoner...
Identation error
[reasoning] Basic support for symmetric predicates

Currently only add the symmetric statements for owl:differentFrom,
owl:disjointWith and owl:sameAs
Bumped to 0.7
Improved a lot support of literals

Literals defined using the Turtle syntax are now recognized properly
which also help determining if a property is an object or a datatype
property.

On the way, the statement lexer (shlex) has been replace by simple splitting
on spaces. Seem ok, but more test would be welcome to ensure minimalkb
behave correctly with malformed statement.

As a side-effect of the new lexer, quoted string are stored as quoted string
and hence kb.lookup can not search anymore in the label. We can certainly
improve that, but I could not quickly find a SQL workaround in sqlite.about()