Logger: Implemented compile-time configuration support

Fix dependency generation for built programs
Fix depenfencies for auto-generated sources

Make all include path's relative
Add 'senf/Packets.hh', 'senf/PPI.hh' and 'senf/Socket.hh'

PPI: Add documentation
Utils: Make Logger macros define empty stub types

PPI: Implement ActiveFeederSource and ActiveFeederSink debug composites

PPI: More documentation
PPI: Implement IdleEvent and ActiveFeeder
PPI: add Module::running() member
Scheduler: Remove MinTimeout (not needed with ClockService working)

PPI: Add additional unit testing

PPI: Fix PassivePackeSink: provide front() instead of back() members
PPI: Provide specializations for void-argument callbacks in Events and Route
PPI: Add notifyThrottle/notifyUnthrottle to EventDescriptor
PPI: Re-implement routing classes using a traits-based implementation
PPI: Add Route unit testing (mainly testing throttling)

PPI: Implement throttling
PPI: Implement ModuleManager and ppi::init
PPI: Implement ThresholdQueuing
PPI: Hugely extended routing classes

PPI: Some small bugfixes to make ppitest work (not only compile :-) )
PPI: Add DebugModules