Consider including an option to control request timeout for unifiedsearch

Hello,

my client recently ran into an issue where intermittent network-failures caused Find-calls to time-out. In order to mitigate similar issues it would be convinient if there was some way to control the timeout through the public API. Here are a few modest suggestions where any or all would do:

1. Add an async overload for EPiServer.Find.ClientExtensions.UnifiedSearchFor with a cancellation-token parameter. 
   
   
2. Add a timeout-property to EPiServer.Find.IClient.Settings
   
   
3. Add a timeout-parameter to EPiServer.Find.SearchExtensions.GetResult

kind regards // Fredrik Johansson