Merge pull request #2 from libdns/feature/readme-add-developing-section

Add contributing instructions to README.md

Add missing struct

Add trailing period for libdns -> leaseweb models

Leaseweb seems to be open to both but some manual string compares failed due to mismatch here.

Remove left over code from testing

Fix trailing dot in zone and adding zone in body of call to Leaseweb

Un-export structs used only for this provider