Directory System and Example

This update should shed light on how to use the memory system.

1. Directory System
- Can create Directories now that are stored in memory. (do_mkdir)
+ Follow this example for creating files as well.
- Can add the directory to it's parent directory.
(add_dir_to_dir_child_list)
- Removed the need for structs, everything is in the partition like it's
supposed to be.

2. Descriptor
- Actually has useful information, such as current diretory, free blocks
ammount, and more!

3. Tests are at the end of Root for convenience.