Allow appending custom querystring parameters

[alhardy]

We are using a custom OAUTH implementation to authenticate with elastic search via a token passed as a query string parameter.

The changes in the two commits just allow ConnectionSettings to be instantiated with a NameValueCollection whose key values are appended to the connection URI as query string parameters.

[Mpdreamz]

Hi @alhardy

Many thanks for this PR and sorry for not getting on this quicker! It will probably be another couple of days before I can review and pull.

[Mpdreamz]

I merged this in the master but with the following changes:

• Removed the second constructor, call SetGlobalRequestParameters(NameValueCollection q) on ConnectionSettings instead.
• The unit tests for copy key test failed as they were written source.CopyKeyValues(dest) but they were implemented as dest.CopyKeyValues(source); I liked the unit tests version better so i changed the implementation.

Thanks @alhardy :)

[alhardy]

Great thank you. When will these code changes be available via nuget?