Use SWIG directors to make map and layer projections useable

[sgillies@…]

For Python at least.  I forsee usage like

>>> mapobj.projection = 'init=EPSG:4269'
>>> mapobj.projection
'init=EPSG:4269'

We can simply treat the projection attribute of maps and layers
as strings and let the Python directors call the needed C code
behind the scenes.  Ruby also has directors and Perl will
eventually.

[sgillies@…]

closing this, have better ideas for projections.