Fix r_modular externalptr error

Add a swig typemap(scoerceout) so that swig doesn't try to recast the nice matricies and numeric vectors we have created in our typemap(out) as an external pointer. All R tests pass successfully now. Also bump swig library version dependency to 2.0.5 when building the R modular bindings because 2.0.4 had a bug that makes them essentially useless. Tested with swig 2.0.4 (fails), 2.0.5, 2.0.11 and current git master.