minor, initialise the sum in the caev file reader

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, provide --total-return mode

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
test, provide clit tests for total return mode

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'feat/total-ret'

* feat/total-ret:
  test, provide clit tests for total return mode
  minor, provide --total-return mode
  minor, initialise the sum in the caev file reader