GTiff, MBTiles, Rasterlite: use GDAL_OF_INTERNAL flags

git-svn-id: https://svn.osgeo.org/gdal/trunk@28027 f0d54148-0727-0410-94bb-9a71ac55c965
JPEG: optimize whole image reading with dataset IRasterIO()

git-svn-id: https://svn.osgeo.org/gdal/trunk@28028 f0d54148-0727-0410-94bb-9a71ac55c965
GPKG: add overview reading

git-svn-id: https://svn.osgeo.org/gdal/trunk@28029 f0d54148-0727-0410-94bb-9a71ac55c965
Add GDAL_OF_INTERNAL flag to allow a dataset not to be globally visible. Saves a mutex to be taken, less verbose debug traces, and enables to avoid implementing error-prone CloseDependentDatasets()

git-svn-id: https://svn.osgeo.org/gdal/trunk@28030 f0d54148-0727-0410-94bb-9a71ac55c965
Merge branch 'trunk' into trunk_travis_macosx