Rename some of the Writer types

Signed-off-by: John Else <john.else@citrix.com>
Store the output file path as part of FileWriter's state

Signed-off-by: John Else <john.else@citrix.com>
Exit on sigint so we don't try to cleanup twice

Signed-off-by: John Else <john.else@citrix.com>
FileWriter unlinks shared file on cleanup

Signed-off-by: John Else <john.else@citrix.com>
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Signed-off-by: John Else <john.else@citrix.com>