* handler: Implement prototype of new locking back-end
* memorylocker2: Switch to channel for release notification
* handler: Update locker interface
* handler: Add method to close body with error
* memorylocker: Replace with new implementation
* filelocker: Adjust methods to match interface
* handler: Introduce new httpContext
* handler: Implement upload interruption
* handler: Adjust tests to new inferfaces
* handler, memorylocker: Cancel context to avoid leaks
Marius