Initial commit
delete some useless file
remove test*.c
rename some c file
delete io_demo.cpp
fix itoa, add main function into convert.c
反转字符串时，循环终止条件应为:j > i，而不应该i != j， 因为当i自增而
j自减，不一定保证i一定等于j.
Merge http://github.com/krystism/Algorithm