Fixed incorrect HID interface class and subclass values in the Mouse and KeyboardMouse demos (thanks to Brian Dickman).

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.

More documentation changes for better module-level documentation rather than file-level documentation.

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