added strcmp func
added strcmp func

added int strcmp(char const* str1, char const* str2)

Compares characters in two strings pointed by str1 and str2.
Returns 0 if strings are identical, 1 if value in str1[i] > str2[i], -1 if value in str1[i] < str2[i].
vlad007700BC/my_string.h,vlad007700BC/my_string.h