Faster, better WAV Trigger firmware update

For any of you anxious to be on the cutting edge, I just posted a preliminary version of the next major firmware update for the WAV Trigger. An optimized mix engine now supports 12 stereo voices by default with pretty much any microSD card - that's a 50% speed improvement over the previous version. At the same time, the trigger latency (time from an active trigger to sound coming out) has been halved to a maximum of 12 msecs, typically 8 msecs. Check out the evidence: 

In addition, the WAV Trigger now provides firmware volume faders for smooth volume transitions: fade-ins, fade-outs and crossfades between tracks. The WAV Trigger Arduino Serial Library has been updated with functions that take advantage of the new faders, making it easy to create smooth transitions between tracks without Arduino processor overhead.

Attack (fade-in) and Release (fade-out) times have been added to the MIDI implementation so that MIDI controllers can be used to dynamically change attack and release times while playing as a polyphonic sampler. This feature, along with the increased voices and reduced latency, makes the WAV Trigger even more of a musical instrument.

And wait, there's more! Due to popular request, I've added a new Load Track function that allows preloading up to 12 tracks, and a new Resume All In Sync command that starts all preloaded tracks at the exact same sample, meaning that up to 12 tracks can be started and played completely sample-locked with one another.

Also, I fixed a long-standing bug with long FAT32 directories that prevented tracks from being played from cards that had a lot of deleted directory entries. (The fix, quick-reformatting the card, is no longer necessary.)

The new firmware is available on the download page, and the new serial commands have been added to the User Guide. Please let me know if you have any issues.