Revert ultrasonic sensor to non-interrupt mode

[OttoWinter]

Description:

The ultrasonic sensors must be generating a short pulse on the echo pin when trigger is pulsed. No good way to fix that with interrupt mode.

Related issue (if applicable): fixes https://github.com/esphome/issues/issues/147

Pull request in esphome with python changes (if applicable): esphome/esphome# Pull request in esphome-docs with documentation (if applicable): esphome/esphome-docs#

Checklist:

• [ ] The code change is tested and works locally.
• [ ] The code change follows the standards

If user exposed functionality or configuration variables are added/changed:

• [ ] Documentation added/updated in esphome-docs.