Merge pull request #2 from asfadmin/master

pull latest from master
Merge branch 'master' of github.com:asfadmin/ASF_MapReady
Add handling of "no data" value for GeoTIFFs in import/export/asf_view
Incorporated the new no data field into the normal geotiff initialization code
Merge pull request #189 from khogenso/master_ar

Master branch with no-data value fix from devel only