Further compatibility changes & fixes

 * Changes from 0.9:
 *  - smartPlacement option removed, deprecated
 *  - default params compatibility for IE
 *  - auto progress bar was killed in changes 0.7 -> 0.8 due to Bootstrap sanitizer, this is readded
 *  - major change to manipulation of BS4 popper.js for orphan steps
 *  - change to implementation of backdrop