Update charted to 0.4.8 and roll

packages/path/README.md

 A comprehensive, cross-platform path manipulation library for Dart.
 
 The path package provides common operations for manipulating paths:
 joining, splitting, normalizing, etc.
 
 We've tried very hard to make this library do the "right" thing on whatever
 platform you run it on, including in the browser. When you use the top-level
 functions, it will assume the current platform's path style and work with
 that. If you want to explicitly work with paths of a specific style, you can
 construct a `path.Context` for that style.
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 [Context] and give it an explicit [Style]:
 
 ```dart
 var context = new path.Context(style: Style.windows);
 context.join("directory", "file.txt");
 ```
 
 This will join "directory" and "file.txt" using the Windows path separator,
 even when the program is run on a POSIX machine.
 
+## Stability
+
+The `path` package is used by many Dart packages, and as such it strives for a
+very high degree of stability. For the same reason, though, releasing a new
+major version would probably cause a lot of versioning pain, so some flexibility
+is necessary.
+
+We try to guarantee that **operations with valid inputs and correct output will
+not change**. Operations where one or more inputs are invalid according to the
+semantics of the corresponding platform may produce different output over time.
+Operations for which `path` produces incorrect output will also change so that
+we can fix bugs.
+
+Also, the `path` package's URL handling is based on [the WHATWG URL spec][].
+This is a living standard, and some parts of it haven't yet been entirely
+solidified by vendor support. The `path` package reserves the right to change
+its URL behavior if the underlying specification changes, although if the change
+is big enough to break many valid uses we may elect to treat it as a breaking
+change anyway.
+
+[the WHATWG URL spec]: https://url.spec.whatwg.org/
+
 ## FAQ
 
 ### Where can I use this?
 
-Pathos runs on the Dart VM and in the browser under both dart2js and Dartium.
-Under dart2js, it currently returns "." as the current working directory, while
-under Dartium it returns the current URL.
+The `path` package runs on the Dart VM and in the browser under both dart2js and
+Dartium. On the browser, `window.location.href` is used as the current path.
 
 ### Why doesn't this make paths first-class objects?
 
 When you have path *objects*, then every API that takes a path has to decide if
 it accepts strings, path objects, or both.
 
  *  Accepting strings is the most convenient, but then it seems weird to have
     these path objects that aren't actually accepted by anything that needs a
     path. Once you've created a path, you have to always call `.toString()` on
     it before you can do anything useful with it.
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  *  It understands that "/foo" is not an absolute path on Windows.
 
  *  It knows that "C:\foo\one.txt" and "c:/foo\two.txt" are two files in the
     same directory.
 
 ### What is a "path" in the browser?
 
 If you use this package in a browser, then it considers the "platform" to be
 the browser itself and uses URL strings to represent "browser paths".