Remove stray state variable from the CDC host class driver.

Fix issue in CDC device class driver where received data the size of the data endpoint could lock up the driver.

Further work on the new CDC and HID host mode class drivers.

Reset changelog et. al. to reset development information for the new version currently under development.

Change Host mode class driver Pipe configuration routines -- better to let the application fetch the configuration descriptors once, and then pass them to each class driver in turn.

Add new MouseHost Class Driver demo, unfinished, to allow for better testing of the new prototype Host Mode Class Driver framework. Flesh out start of a HID class Host mode class driver.

Completed host CDC class driver enumeration code.

Added new TOTAL_NUM_CONFIGURATIONS option, removed USE_SINGLE_DEVICE_CONFIGURATION compile time option (but silently convert it to USE_SINGLE_DEVICE_CONFIGURATION internally for compatibility).

Added new USE_FLASH_DESCRIPTORS compile time option. By default, descriptors can now lie in mixed memory spaces (specified by a new parameter to the CALLBACK_USB_GetDescriptor() function) unless one of the USE_*_DESCRIPTORS compile time option is specified.

Remove all Host mode class demos other than the CDCHost class driver demo, so that they can be re-added as they are made once the host mode class framework is designed.

Fixed USB_Host_SendControlRequest() not re-suspending the USB bus when initial device ready-wait fails.

Fixed USB Pad regulator not being disabled on some AVR models when the USB_OPT_REG_DISABLED option is used.

Added USE_INTERNAL_SERIAL compile time option to automatically read out the internal unique serial number as the device's serial number descriptor on supported AVR models.

Re-add in simple scheduler for compatibility with legacy code, mark all scheduler related files as deprecated.

Break device mode class driver interfaces into seperate config and state structs which are then combined, for clarity. Move device mode class driver interfaces back into the device mode class driver headers from the common class headers to make room for host class interfaces.

Enhanced class drivers to use the same public/private section seperations as other portions of the library.

Split out common defines/types from class drivers into a seperate common class driver directory.

Make central USB Class driver dispatch headers, used for both device and host modes.

Move new Class Driver powered demos to a new ClassDriver subdirectory, re-add old low level demos to a LowLevel subdirectory.

Moved out each demos' functionality library files (e.g. Ring Buffer library) to /Lib directories for a better directory structure.

Renamed Serial_Stream driver to SerialStream to remain consistent with the rest of the library's naming scheme for files.

Seperated out OTG, Device and Host mode demos into seperate folders for clarity. Adjusted makefiles so that the path to the LUFA library can be set in one place.