Added MS_Host_TestUnitReady() and MS_Host_ReadDeviceCapacity() to the host mode Mass Storage Class driver.

Add SCSICodes.h to the Class Driver Common folder, and automatically include it in both the Host and Device Mass Storage Class drivers. Delete existing version from the ClassDriver MassStorage device demo's /Lib/ folder.

Oops: Really disable building of Projects/Host/ClassDriver directory in the Projects/Host/ makefile.

Add more skeleton functions and definitions to the Mass Storage Host mode Class driver.

Made Endpoint_Write_DWord_* functions echo the structure of the matching Endpoint routines for clarity.

Added  ATTR_NON_NULL_PTR_ARG() attributes to the class drivers to improve user code reliability by disallowing explicit NULL pointers as pointer parameters in function calls where the parameter must not be NULL.

Disabled building of the Demos/Host/ClassDriver directory until Host Mode Class drivers are complete to prevent build errors in the meantime.

Minor updates to the unfinished SideShow demo for clarity.

Added unfinished MassStorageHost class driver demo.

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 StdRequestType.h, StreamCallbacks.h, USBMode.h from the LowLevel USB driver directory to the HighLevel USB driver directory, where they are more suited.