big rewrite

new package structure
rename imagemover to photoimport
rewrite ImageFinder (now ImportSource) and ImageGroup (new ImportGroup) to allow new features
many other changes to increase consistency and improvements
enable use of locales and exifExtensions, further cleanup + testing
Enabled the use of Date and DCF number filters and file verification
Fix checksum computation to discern failed computations, add more javadocs
Add readme file with program description