Fix typos using codespell

CHANGES

README.md

SConstruct

doc/Makefile.am

examples/dump_psnr.c

examples/dump_video.c

examples/encoder_example.c

examples/png2theora.c

examples/splayer.c

examples/tiff2theora.c

include/theora/codec.h

include/theora/theora.h

lib/Makefile.am

lib/analyze.c

lib/arm/armcpu.c

lib/decinfo.c

lib/decint.h

lib/decode.c

lib/encint.h

lib/encode.c