(FontLayoutCmdOTF): This type deleted.

(FontLayoutCmdOTF): This type deleted.
(FontLayoutCmd): Type of the member otf changed..
(load_otf_command): Adjusted for the format change of otf command.
(load_command): Likewise.
(free_flt_command): Unref cmd->body.otf.
(run_otf): Ajusted for the type change of otf_cmd.
(run_command): Ajusted for the type change of otf_cmd.  On
debugging, print ctx->combining_code.
(mfont__flt_run): Initialize ctx's members code_offset,
combining_code, and left_padding to 0.