add xlutils to setup.py
allow login to not case sensitive for username
add case insensitive backend
Merge pull request #40 from nyaruka/login_not_case_sensitive

allow login to not case sensitive for username
build timezone based on current date
pass update_fields to save for task log method
Merge pull request #41 from nyaruka/fix

pass update_fields to save for task log method
save the task after records are created to save import results
Merge pull request #42 from nyaruka/fix

save the task after records are created to save import results
merge