[features] checking what happens when no password file exists
Adding acceptance tests to default test target
Removing popen3 TODO item; this item has started but with pexpect
Adding the --onecmd command line option

Also adding acceptance tests of this feature
[features] making onecmd error test more explicit
[features] closing process before checking exitstatus

According to the docs, this is necessary so that the exit status can be
properly checked.
[features] adding --onecmd exit test (wip)
[features] improving "trove exits uncleanly" test method name
Adding a --file command line option

Now the password file can be passed in at run time from the command line
Correcting handling of the onecmd() option
[features] adding wip empty password test
[features] testing for error when --file without arg is used
[features] the empty password file scenario now passes