Add function to get the next name of file in the romfs
Add function to get all the name of files
1.This function will return the number of files.
2.This function will store all name into a buffer and use '\0' to express the end of name.
Use enum to specify the type of commands
Add function to process the command ls
It can't get the correct name of files now.
Modify getNextFileName function
when it isn't have the next file, it will reutrn NULL
Fix the error of getNextFileName function
Fix the error of the name of filesystem and clear the buffer to zero
Fix the error of the getNextFileName function
1.At the end of the function, the buffer doesn't be clean.
2.Let the charater correctly be  stored in the buffer.
Fix the error of the getNextFileName function
1.Fix the return value.
2.Use the '\t' to represent the end of the name of file.