Extension of mapproxy to support new projections,
layers and services (WMTS)

All available layers and timestamps as physical tiles in S3,
but not use of keyword 'current'

- improving documentation and README for mapproxy
- removing OSM layers from config
- coping with empty parts in template
- adding missing projections in WMS
- optimized apache settings
- only requesting the needed WMTS tiles
- typo and wording
- removing unused tilematrixset
- more tests
- wmts axis order issue
- etc.
Merge pull request #1040 from geoadmin/mom_mapproxy_extension

Extension of mapproxy to support new projections (WMTS)