Add Backoff and ramp up periods in padding manager (lynckia#1741)

Repair GenericOneByteExtension memory leak. (lynckia#1735)

Fix stream republishing (lynckia#1725)

Fix mediaStream priority initialization (lynckia#1721)

Implement Unified Plan (lynckia#1602)

Implement Unified Plan (lynckia#1602)

Bump xmlhttprequest from 1.5.0 to 1.7.0 in /spine (lynckia#1705)

Bump xmlhttprequest from 1.5.0 to 1.7.0 in /spine (lynckia#1705)

QualityManager cleanup (lynckia#1698)

Fix bad check (lynckia#1701)