Geointerface conversions

[rafaqz]

This PR adds the new geointerface_geomtype local methods, updates convert to not use coordinates, and adds methods to all functions that will work on any compatible geometries.

There are some extra methods needed for some constructors to make convert more consistent.

Its not really practical to test this without wrapper types, the test objects are too limited:

So also waiting on JuliaGeo/GeoInterface.jl#78

We may as well review this now as its basically ready to go, just needs 78 to work. @jw3126 if you would also like to review this that would be helpful.

[rafaqz]

This should be good to go. It's a breaking change because I have renamed Base.contains to LibGEOS.contains, otherwise we can't accept other geometries in it without piracy.

We can lump it with #155

I made this non breaking to reduce friction, there are now both Base.contains and LibGEOS.contains methods. We can remove the base method when we do #155

[rafaqz]

Bump

@visr @evetion @jw3126 can I get a review for this?

[visr]

Left one suggestion, but this looks good to me! This will be great to have.

It would be nice if we could avoid the .ptr added in this PR, but it seems like that is probably better addressed separately.

[rafaqz]

Yes I was thinking about adding a better internal getx etc method, but it can be separate.