Tweak usage formatting

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Organize arguments into logical sections

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Use the return value of schedule_suite()

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Split prepare_and_schedule() out of main()

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Don't schedule an email job if email isn't set

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Add default results_email

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Do everything that schedule_suite.sh does

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>