Changed XPLAINBridge project to be both a USB to USART bridge and a PDI programmer, based on the state of a mode select pin.

Clean up and add more comments to the AVRISP-MKII project. Make sure the SPI_MULTI command handler supports multiple packet responses. Use slightly smaller/faster repeated indirect-load commands when retrieving the PDI target's memory CRCs.

Added support to the MIDI Class drivers for packed data, where multiple MIDI events are packed into a single USB packet. Added new MIDI Class driver flush routines to override packing behaviour.

Reduced guard bit time in the AVRISP project PDI/TPI protocols to reduce the time needed to reverse the data communication direction.

Fixed AVRISP PDI race condition where the guard time between direction changes could be interpreted as a start bit. Fixed TPI interface lines not being changed correctly when in bit-banged TPI mode.

Change the AVRISP project's RESET LINE makefile tokens to AUX LINE, as it is not always used for target reset.

Fix TPI NVM Write handler -- AVRStudio sends out writes in page sized chunks, not byte sized chunks.

Add first draft of the TPI NVM commands for reading, writing and erasing a target. Needs testing when physical access to a part is available.

Add dummy undocumented TPI XPROG parameters to the AVRISP project so that TPI programming mode can be entered.

Fix mistakes in the XPROGTarget.c/.h files for TPI mode software USART clock rate and PDI mode XPLAIN board autoconfiguration.