Check extension
Handle CSV/JSON separately. No XML
Dirty when added/removed
Check VM property changes.
accept
Check everything else
Move code to ProjectVM
style
Merge pull request #147 from KSHSK/dirty-flag

Set dirty when changes are made
Merge branch 'master' into file-type
Merge pull request #145 from KSHSK/file-type

Only allow CSV and JSON files
Merge branch 'master' into usmap