added open layers tms changes
gap changes made by bart to add tms support. these are changes merged to gap in commit 7d30f2d5ce12f61e3f67673815eff94c8841ab8b as well as c381be9588bf0e101a5c54ed2b3fafa3e561b5b1
Merge commit 'b184514dc94d964e5ce6b8b8320b3a07b0ae353b'