Fixed incorrect ENDPOINT_EPNUM_MASK mask preventing endpoints above EP3 from being selected (thanks to Jonathan Oakley).
Removed STREAM_CALLBACK() macro - callbacks now use regular function definitions to clarify user code.
Removed DESCRIPTOR_COMPARATOR() macro - comparators should now use regular function definitions to clarify user code.
Remove the saving of the USB_GetNextDescriptorComp() return value in all host demos, since it went unused anyway; replaced with a simple check against the success error code for clarity.
Capitolised the "Descriptor_Search" and "Descriptor_Search_Comp" prefixes of the values in the DSearch_Return_ErrorCodes_t and DSearch_Comp_Return_ErrorCodes_t enums.
Minor documentation improvements.