add /core to .gitignore
update curious_alloc for C++11

without the templated construct() and destroy() methods, every allocation
caused an unnecessary MidiEvent copy construction.
rework benchmark code, print results on unload
relax parameter checking of *Event() functions

since these are called at runtime, accept velocity and controller values
that are out of bounds.
allow engine with no input or output ports
make das::regex default-constructible and copyable
refactor ALSA port connecting

avoid deep nesting, use ClientPortInfo struct where applicable, and move the
actual connection to a separate function.
ignore unmatched note off events in VoiceFilter()

better than raising an exception...
fix ALSA connection error reporting

broken during recent refactoring.
fix dropped events when using output_event()

never attempt to write JACK events out of order. this could previously
happen if output_event() or the Panic() unit was used.
add mididings -p option for a simple event logger