Expose PoolingOptions setters that set both min and max

PoolingOptions enforces the invariant "min <= max" for pairs of related options: set(Core|Max)ConnectionsPerHost and set(Min|Max)SimultaneousRequestsPerConnectionThreshold. This is necessary because these options can be updated at runtime.

This is a bit annoying if you need to modify both options, because the correct order to call the setters will depend on the previous values (ex: given currentMin = 4 and currentMax = 6, if newMin = 7 and newMax = 9 you need to call setMax first; whereas if newMin = 1 and newMax = 2, you need to call setMin first).

Expose a new setter that takes both values and takes care of calling the individual setters in the correct order, for example: