Feature/geo hash filter

[robertlyson]

Hello,

this is short summary what I have done to implement this feature:

I've added new property to GeoPointMapping: GeoHashPrefix.
GeoPointMappingDescriptor has been changed as well.

I've created new classes: GeoHashCellFilter, GeoHashCellFilterDescriptor and GeoHashCellFilterConverter

At the end I've prepared FilterContainer and FilterDescriptor to handle filter.

PS:
These classes contain tests for the issue: GeoHashCellFilterJson and GeoHashCellFilterTests

[gmarz]

@robertlyson Typically, we do not fully namespace our public API classes. This should be changed to just Nest.

[gmarz]

@robertlyson Awesome! Thank you for implementing this. 👍

I left a few minor comments regarding the Nest.DSL.Filter namespace, which is a simple fix. Also, it looks like the build broke when you renamed GeoHashCellFilter.cs:

Source file 'Search\Filter\Singles\GeoHashCellFilter.cs' could not be found

Looks like the rename never made it to the csproj file.

Other than that, this LGTM.

[robertlyson]

@gmarz Thank you for your feedback.

I've pushed my fixes.
In case of any questions, let me know.

Thanks.

[gmarz]

Great, thank you @robertlyson! Changes look good.

One last request, would you mind signing the CLA so we can pull this in?

[robertlyson]

@gmarz Done.