Enhance shp2pgsql to be able to load into new geography type

[robe]

I'm thinking would be nice if combined with #229 so that we can if someone has data in a non-4326 srid, they can load and transform in one shot.

Have we coalesced the logic of the gui, core, etc yet? We probably should do that before this step.

[robe]

Okay I guess #204 answers my question about the merge -- still on our todo

On a slightly different note -- I haven't tested pgsql2shp so not sure if the autocasting behavior of geography to geometry makes it autowork already.

[pramsey]

Added support to the CLI loader (-G option) at r5040

[pramsey]

Added support to the GUI loader at r5042

[mcayland]

Looks reasonably sensible, although there doesn't appear to be any regression tests for the geography code which might be a good idea.

[pramsey]

Added support to the CLI dumper (automatically senses and dumps geography columns if they are present) at r5051. If the -g option is present, uses that geocolumn, if not, picks the first one it hits whether it's geography or geometry.

[pramsey]

Regression task added in #358.