so that the specification of the name and dimensions are optional in property dictionaries.
Update tutorials so that the name of the dimensionedScalar property is
no longer duplicated but optional dimensions are still provided and are
checked on read.
Note that currently when transportProperties is changed sigma is re-read
from this dictionary but cAlpha is read from fvSolution but cAlpha is
not re-read when fvSolution is changed but transportProperties is not
touched. To avoid this problem cAlpha would need to be moved to the
transportProperties dictionary which is not ideal or moved out of the
interfaceProperties class back to the top-level solver.
Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1657
