Reduce qDebug() usage
MidiInterface: considers as "used" when a mapping have been assigned to interface
MidiInterface: on close(), closes output if has one
MidiInterface: load/flush associated MidiMapping on connection/disconnection

This allow to only have mapped AND connected devices mapping in memory.
It should reduce multiple-configured-but-unplugged-devices configuration's CPU usage. (Not the most users, but hey, that is an improvement ;-))
MinoTrigger: add a cache for feedback and a trick to refresh associated Midi device

This patch allow to refresh LEDs status on nanoKontrol 2 when role is mapped to control.
Unfortunatly, this does not work on device hotplug: it seems we need to wait nanoKontrol2 to be ready to receive LEDs status?
MidiMapper: registeredRoles() now returns a sorted list

User now have a sorted list of roles in role combobox (Midi Mapping tab from ConfigDialog)
MidiInterface: new sendMessage(QByetArray) function

This function takes a QByteArray and copy it into std::vector<unsigned char> as expected by RtMidi.
Thanks to Qt, its, the most of time,  easier to manipulate QByteArray than std::vector<unsigned char> but in our case it costs a memory copy, so dont abuse of it :)
MidiInterface: new sendIdentityRequest()

MidiInterface is now able to send a MIDI SysEx message to request identity of device accordingly to MIDI specifications.
MidiInterface: handle SysEx replies more properly.

MidiInterface now constructs a description string using "Identity Reply" from MIDI device.
It could be a good way to do some magic stuff (autodetect corresponding mapping, autodetect multiples devices, etc.) using Manufacturer ID and family model ID.
MidiInterface: new Korg specific functions (RFU)

Here, we may have something useful to download a dedicated configuration to Korg device (tested with nanoKontrol 1 and 2) for best Minotor experience (ie. the factory default map does not allow user to use 4 scenes with nanoKontrol 1)