GEOS-6257, IE issues that arise when it excepts text/html
Merge pull request #416 from NielsCharlier/mbtiles

Mbtiles GetMap outputformat
[GEOS-6243]:EmptyMosaic: REST APIs support
Merge pull request #431 from geosolutions-it/GEOS-6243

[GEOS-6243]:EmptyMosaic: REST APIs support
Mbtiles/geopkg: remove duplicated abstract class + fix various bugs