iscsi-ls: add --url parameter

Signed-off-by: Peter Lieven <pl@kamp.de>
Merge pull request #68 from plieven/iscsi-ls-url

iscsi-ls: add --url parameter
UTILS: Check that an iscsi url was provided on the command line before strdup()ing it
SCSI MODESELECT: leave the 4/8 byte header completely blank.
The convention is to not fill this header in when sending modeselect to a target
Add MODESENSE6/10 and MODESELECT6/10 support
Merge branch 'master' of github.com:sahlberg/libiscsi
Add POWER_CONDITION modepage marshalling/unmarshalling
TESTS: clear unit attention after changing SWP settings in the readonly test
Add SANITIZE_IN_PROGRESS ASCQ
Dont reference *pdu after it has been freed
Dont fail the login just because a sanitize is in progress
Add a test that a sanitize operation will continue across resets

Verify that abort task/abort task set/lun reset/warm reset/cold reset
and full blown session failures will not affect a sanitize that is in
progress
TESTS: Inquiry is still allowed while SANITIZE is running
TESTS: READ10 and STARTSTOPUNIT should fail while sanitize is in progress

Other commands should fail too  but we dont need to test them all