Restore binary compatibility of IncOptions constructor.

The 6f7467363a5de9272ecc2f3dd4cd371d6378627f introduced support for new
fields in IncOptions class but broke binary compatibility. Let's add
overloaded (and deprecated) constructor which fixes binary compatibility
of constructor.

NOTE: The IncOptions in zinc is a case class so restoring full binary
compatibility (for example, of copy method) is not feasible.
Merge pull request #59 from gkossakowski/issue-44

Restore binary compatibility of IncOptions constructor.