(set|remove)_schedule should respect Resque.inline

much like #503 on delayed jobs, setting/removing schedules should also respect Resque.inline

I am moving Resque.schedule = lines from rake task to rails initializer,
to make schedules available in schedule tabs https://github.com/resque/resque-scheduler/issues/541#issuecomment-224886592 .
But doing so breaks my ci test environments, where I set Redis.inline = true and still gets complains Redis::CannotConnectError (exactly what @benthorner is seeing at https://github.com/resque/resque-scheduler/issues/541#issuecomment-218894599 )

README should be updated, schedlue tab was maybe the reason for https://github.com/resque/resque-scheduler/issues/563#issuecomment-229021293 ,
and I might be (very likely) misunderstanding about difference between (persisted|non-persisted schedule
(I am not using dynamic scheduler, and really confused which one I should be using
when all I want to do is load schedule from yaml, update schedule on deploy by restarting scheduler, use schedule-tab for manual kicking)

but ANYWAYS (set|remove)_schedule should work without connection to redis when Resque.inline is set to true.

Start by tracing the set_schedule and remove_schedule entry points and compare their intended inline behavior with the delayed-job change in issue #503. Verify the behavior when Resque.inline is true and Redis is unavailable, then check the README context around persisted and non-persisted schedules. Done means both operations work without a Redis connection in inline mode and the documented behavior is clear.