sed -i -e 's/變量/變數/g' coroutines_in_c.tex
little modify
move coroutine.h to appendix
sed -i -e 's/語句/敘述句/g' coroutines_in_c.tex
little modify
sed -i -e 's/通過/透過/g' coroutines_in_c.tex
little modify some sentences.
	new file:   code/cr_by_goto.c
	new file:   code/makefile