NH-3987 - Re-implement NhQueryable options

[fredericDelaporte]

NH-3987 Re-implement NhQueryable options.

At least that way, adding more options should be way less intrusive.

Instead of having one extension method per option, we now would have a single SetOptions extension method, taking a delegate for setting options with a IQueryableOptions object.

query = query.SetOptions(o => o.SetTimeout(10).SetCacheable(true));

I could have directly exposed the IQuery instead but well, it would have exposed undesirable features in a Linq context I think.

[fredericDelaporte]

The SetOptions parameter does not end up in cache parameters key, so it does not cause an issue. and keeping the delegate will allow more code simplification if we mutualise later the options interface on all query API.

[fredericDelaporte]

Updated the reference documentation too. And fixed the SetOptions xml comment.

[fredericDelaporte]

Rebased for resolving conflicts x2.

[hazzik]

I was thinking. Do we need to have the separate method of options? Why not include it into .Query(options)?

[fredericDelaporte]

Well I have tried at first something similar. But there is a roadblock: each Linq call creates a new NhQueryable, which only gets the expression and the provider. I have not found better ways for transmitting the options than keeping them in the expression. (The provider creates new NhQueryable by only having the expression to use for that. We do not have any reference to the original NhQueryable from which the expression was derived. See IQueryProvider.CreateQuery methods.)

Then, only allowing setting the options when obtaining the queryable from the session may be limiting: I frequently build different queries from the same queryable base on which I have already applied some Linq transformations, and those resulting different queries may not have the same options requirements.

[fredericDelaporte]

Thanks Alexander,
I will merge that after some more PR on fixing tests.