xmerge: Integer & Boolean Parsing

Change-Id: I9553121a7faf10799c9d9a53336470cb2634c4ee
Reviewed-on: https://gerrit.libreoffice.org/11329
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>