README updates

COPYING

-Copyright (c) 2007-2020 Yoran Heling
+Copyright (c) 2007-2021 Yoran Heling
 
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the

README

-ncdu 1.15.1
-===========
-
-DESCRIPTION
-
-  ncdu (NCurses Disk Usage) is a curses-based version of
-  the well-known 'du', and provides a fast way to see what
-  directories are using your disk space.
-
-
-REQUIREMENTS
-
-  In order to compile and install ncdu, you need to have
-  at least...
-
-  - a POSIX-compliant operating system (Linux, BSD, etc)
-  - curses libraries and header files
-
-
-INSTALL
-
-  The usual:
-
-    ./configure --prefix=/usr
-    make
-    make install
-
-  If you're building directly from the git repository, make sure you have perl
-  (or rather, pod2man), pkg-config and GNU autoconf/automake installed, then
-  run 'autoreconf -i', and you're ready to continue with the usual ./configure
-  and make route.
-
-
-COPYING
-
-  Copyright (c) 2007-2020 Yoran Heling
-
-  Permission is hereby granted, free of charge, to any person obtaining
-  a copy of this software and associated documentation files (the
-  "Software"), to deal in the Software without restriction, including
-  without limitation the rights to use, copy, modify, merge, publish,
-  distribute, sublicense, and/or sell copies of the Software, and to
-  permit persons to whom the Software is furnished to do so, subject to
-  the following conditions:
-
-  The above copyright notice and this permission notice shall be included
-  in all copies or substantial portions of the Software.
-
-  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.md

+# ncdu-zig
+
+## Description
+
+Ncdu is a disk usage analyzer with an ncurses interface. It is designed to find
+space hogs on a remote server where you don't have an entire graphical setup
+available, but it is a useful tool even on regular desktop systems. Ncdu aims
+to be fast, simple and easy to use, and should be able to run in any minimal
+POSIX-like environment with ncurses installed.
+
+## This Zig implementation
+
+This branch represents an experimental rewrite of ncdu using the [Zig
+programming language](https://ziglang.org/). It is supposed to be fully
+compatible (in terms of behavior, UI and CLI flags) with the C version, so it
+can eventually be used as a drop-in replacement.
+
+Since Zig itself is still very much unstable and things tend to break with each
+release, I can't in good conscience publish this rewrite as a proper release of
+ncdu (...yet). I intent to maintain the C version as long as necessary while
+Zig matures and gets more widely supported among Linux/BSD systems. 
+
+This rewrite is a test-bed for various improvements to the design of ncdu that
+would impact large parts of its codebase. The improvements may also be
+backported to the C version, depending on how viable a proper Zig release is.
+
+### Implementation status
+
+Missing features:
+
+- Export/import
+- Most directory listing settings
+- Scaning UI
+- Lots of informational UI windows
+- Directory refresh
+- File deletion
+- Opening a shell
+
+### Improvements compared to the C version
+
+Already implemented:
+
+- Significantly reduced memory usage, achieved by:
+  - Removing pointers between nodes that are not strictly necessary for basic
+    tree traversal (this impacts *all* code in the C version of ncdu).
+  - Using separate structs for directory, file and hard link nodes, each storing
+    only the information necessary for that particular type of node.
+  - Using an arena allocator and getting rid of data alignment.
+- Improved performance of hard link counting (fixing
+  [#121](https://code.blicky.net/yorhel/ncdu/issues/121)).
+- Add support for separate counting hard links that are shared with other
+  directories or unique within the directory (issue
+  [#36](https://code.blicky.net/yorhel/ncdu/issues/36)).
+  (Implemented in the data model, but not displayed in the UI yet)
+- Faster --exclude-kernfs thanks to `statfs()` caching.
+- Improved handling of Unicode and special characters.
+
+Potentially to be implemented:
+
+- Faster --exclude-pattern matching
+- Multithreaded scanning
+
+### Regressions compared to the C version
+
+Aside from this implementation being unfinished:
+
+- Assumes a UTF-8 locale and terminal.
+- No doubt somewhat less portable.
+
+## Requirements
+
+- Latest Zig compiler
+- Some sort of POSIX-like OS
+- ncurses libraries and header files
+
+## Install
+
+**todo**