Bump version to 4.1.0

Cut 4.0.1 release with bug fix (#222)

Default decoded GeoJSON to SRID 4326 (WGS 84) per the spec (#219)

* Default decoded GeoJSON to SRID 4326 (WGS 84) per the spec

The GeoJSON spec [indicates](https://tools.ietf.org/html/rfc7946#section-4) that all GeoJSON should be assumed to use the WGS 84 datum by default. We should be permissive and allow overriding that datum (as we did previously), but I think the correct behavior here is to make the datum explicit in our decoded `Geo.Geometry.t()` values.

This is a breaking change, but one which I expect to have quite little impact on users. (See the CHANGELOG.md for more.)

Resolves #129

* Prepare the rest of the v4.0.0 release notes

* Add final release date

Prepare to release v3.6.0 (#189)

* Prepare to release v3.6.0

* Add release date

Prep for release

Prepare for release

Update Changelog and version

Update version and changelog

Update deps and version

Merge pull request #156 from bryanjos/faster_encode_decode

Encoding and Decoding Well-known Binaries (WKB) using IOData