Why to make param scheduler in extension function .observe() Schedulers.io() by default

[vigidroid]

If we use extension function observe(), Schedulers.io() will be applied by default. This means thread will be automatically switched without awareness if we do not go through the source code of this library, which does not make sense.

I suggest two ways below:

1. make param scheduler = null by default, users will specific it while they wanna a switch.
2. make rxDataBindingsScheduler nullable, therefore users have ability to disable scheduler globally.