Implement ToString trait for GeoJson

Build documentation via rustdoc on travis

Restructure rust-geojson, bump to 0.1

https://github.com/georust/rust-geojson/pull/30#discussion_r30674234

https://github.com/georust/rust-geojson/pull/30#discussion_r30674020

As discussed in #29

Closes #3

Closes #10

Fixes #22

Only allow Object or Null value for Feature properties

Prior to this change, one could do something like:

{"type": "Feature", geometry: ..., propertie...

Replace MultiLineString Ring with Pos

Remove unnecessary `returns`

Improve documentation for types::ring::Ring

For the same reasons as #21

A 'ring' implies that it is 'closed' (the first and last coordinate...

Replace LineString Ring with Vec<Pos>

A 'ring' implies that it is 'closed' (the first and last coordinate are
the same). This is not a...

Utilize HashMap instead of BTreeMap

Relevant documentation:
http://doc.rust-lang.org/std/collections/index.html#when-should-you-use-...

Handle errors when parsing

Removes unnecessary todo

add `Debug` trait to all types

fixes #16

public members for [Feature|Geometry]Collection

Implement from_str

Separate all types into their own submodule

Fixes #9

update to version 1 compatible

Convert project from executable to library