read BigTIFF format
Merge branch 'master' into bigTiff
handle empty strings
allow multiple selections
Merge pull request #12 from arraydev/bigtiff

read BigTIFF format
Merge pull request #13 from arraydev/envi

handle empty strings
migrated missing landsat property from BEAM
(cherry picked from commit 51f5436)
Merge branch 'master' of github.com:senbox-org/beam
Merge pull request #14 from arraydev/layer_assistant_multiple_selections

allow multiple selections