Derive CreateIndexDescriptor from IndexPathDescriptorBase<P,K>

[maximpashuk]

NEST 1.0

Comparing signatures (I simplify signatures a little):

CloseIndex(CloseIndexDescriptor);
GetIndexSettings(GetIndexSettingsDescriptor);
IndexExists(IndexExistsDescriptor);
OpenIndex(OpenIndexDescriptor);
CreateIndex(string index, CreateIndexDescriptor);

In first 4 methods I can use fluent calls to specify index name, like
CloseIndex(x => x.Index("name"))

BUT only in CreateIndex method I must specify index name as first parameter.

@Mpdreamz , I think index-related API should be uniformed to fluent calls.

As I realized from sources, to achieve this CreateIndexDescriptor should be derived from IndexPathDescriptorBase - but probably I am missing something

[Mpdreamz]

+1 CreateIndexDescriptor(string index, CreateIndexDescriptor) should be CreateIndex(CreateIndexDescriptor) and should inherit from IndexPathDescriptorBase<P, K> really nice catch @maximpashuk

We can then add similar extension methods such as CloseIndex(string index) to CreateIndex()

[Mpdreamz]

now implemented, I added the CreateIndex(index, Func<CreateIndexDescriptor, CreateIndexDescriptor> = null) signature back in as extension method