tableName syntactic sugar (ISSUE-75)

As was evident in our "face-to-face" meeting there is a lack of consensus
about the wisdom of having the tableName syntactic sugar. Several of the
questions that arose during this discussion are recorded in ISSUE-75 [1].
Since we have still been unable to come to a shared view of these issues,
in the interest of getting R2RML 1.0 out I propose:

[
PROPOSAL: Resolve ISSUE-75 by removing the tableName syntactic sugar and
simplifying the R2RML schema documentation and property table to reflect
this.
]

-David

[1] - http://www.w3.org/2001/sw/rdb2rdf/track/issues/75