Scheduler/Console: Add 'sys' directory
Scheduler: Implement EventManager and 'sys/scheduler/events' command

Console: Implement LinkNode

Utils: Replace TypeInfo demangle implementation from binutils with cxxabi implementation
Console: Implement Executor chroot and security policy support
Console: Refactor Node::traverse() implementaiton to move code out of template function

Console: Pass ParseCommandInfo instead of ArgumentsRange to the callbacks
Console: Add named aliases for operator overloads ('[]' and '()')
Utils: Document, where impl/demangle.h comes from
Updated the 'Setting up a new project using SENF' documentation

Console: Added non-blocking client output stream
Console: Repeat last command on RET