Github user FlorianHockmann commented on the issue:
https://github.com/apache/tinkerpop/pull/729
> The .net build is failing:
`Double` seems to be a type that we didn't have in the traversal API until
now. It should be simply mapped to `double` in C#. This should only require an
addition to the `toCSharpTypeMap` in Gremlin.Net's
[`generate.groovy`](https://github.com/apache/tinkerpop/blob/master/gremlin-dotnet/glv/generate.groovy#L29).---
