- sys$readlink + readlink()
- Add a /proc/PID/exe symlink to the process's executable.
- Print symlink contents in ls output.
- Some work on plumbing options into VFS::open().
I added a dead-simple malloc that only allows allocations < 4096 bytes.
It just forwards the request to mmap() every time.
I also added simplified versions of opendir() and readdir().
