update filesystem docs

Author: copy

docs/filesystem.md

@@ -38,10 +38,8 @@ filesystem: {
 ```
 
 Here, `basefs` is a json file created using
-[fs2json](https://github.com/copy/fs2json). The base url is the prefix of a url
-from which the files are available. For instance, if the 9p filesystem has a
-file `/bin/sh`, that file must be accessible from
-`http://localhost/9p/base/bin/sh`.
+[fs2json.py](tools/fs2json.py) and the `baseurl` directory is created using
+[copy-to-sha256.py](tools/copy-to-sha256.py).
 
 If `basefs` and `baseurl` are omitted, an empty 9p filesystem is created. Unless
 you configure one of the alternative modes.

lib/filesystem.js

@@ -178,8 +178,7 @@ FS.prototype.load_from_json = function(fs)
 
     if(fs["version"] !== JSONFS_VERSION)
     {
-        throw "The filesystem JSON format has changed. " +
-              "Please update your fs2json (https://github.com/copy/fs2json) and recreate the filesystem JSON.";
+        throw "The filesystem JSON format has changed. Please recreate the filesystem JSON.";
     }
 
     var fsroot = fs["fsroot"];

v86.d.ts

@@ -230,7 +230,7 @@ export interface V86Options {
         baseurl?: string;
 
         /**
-         * A directory of 9p files, as created by [fs2json](https://github.com/copy/v86/blob/master/tools/fs2json.py).
+         * A directory of 9p files, as created by [copy-to-sha256.py](https://github.com/copy/v86/blob/master/tools/copy-to-sha256.py).
          * For more details, see docs/filesystem.md
          */
         basefs?: string;