add PIUIO_Leds driver

The mappings in this driver are specific to the piuio kernel driver, but
once lights mapping is possible this could be made into a generic leds
class driver.
don't set lights for nonexistent lights

duh.
point at the right file in the filesystem
Added WheelItemBase:IsLoaded lua function and associated error.
Added Swap Up/Down option to Edit Alter Menu.
Added Arbitrary Remap option to Alter Menu in Edit Mode.
Merge pull request #284 from Midiman/changes-beta4

Beta 4 theme updates
Added FastNoteRendering preference.
Merge pull request #276 from djpohly/piuio-leds

LightsDriver for /sys/class/leds with new PIUIO kernel module
Merge branch 'master' of https://github.com/stepmania/stepmania
Merge branch 'master' of https://github.com/stepmania/stepmania
Merge pull request #285 from kyzentun/ClearZPref

Added FastNoteRendering preference.
Merge pull request #277 from kyzentun/WheelItemIsLoaded

WheelItemBase:IsLoaded
Merge pull request #278 from kyzentun/EditSwapUD

Added Swap Up/Down option to Edit Alter Menu.
Localized Arbitrary Remap edit mode strings.  Changed track ids for Arbitrary Remap to start at 1.
update OSX mkrelease scripts

This allows OS X devs to bundle either a release or a nightly disk image.  See the updated readme for more information.
Merge pull request #286 from dguzek/OSX-bundle-script

update OSX mkrelease scripts
Fix up HowToPlay graphics
Fix up HowToPlay graphics (2)
Make TwoPartSelection dialog work for all players