added some error checking to list.c, and an empty function
prob01: removed comments from old implementation; prob03: made decode return the new string, rather than printing it; both: made main run only when a macro is available; Makefile: made binaries actually run main; utility.c: changed debug macro name
finally commented the file, and fixed the bug where the base64 output doesn't have the proper padding if the original ascii string's length isn't divisible by 3
added comment explaining why the file looks that way