Paged searches

[SebastianBecker2]

Server limits FindItem to 1000 results.

https://msdn.microsoft.com/en-us/library/office/dn592093(v=exchg.150).aspx shows how to implement paged searches to get all items or a particular subset.

I (already) create a PR for this.

[bkircher]

First steps in master by with 1d0d59b. Thanks @SebastianBecker2.

I guess we need to extend the find_item overload set a bit more to make the API more complete.