Describe this as "a package" and not "a library". (#5)

Closes #4
diff --git a/README.md b/README.md
index 0862e90..0d1db9c 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-A library for testing subprocesses.
+A package for testing subprocesses.
 
 This exposes a [`TestProcess`][TestProcess] class that wraps `dart:io`'s
 [`Process`][Process] class and makes it easy to read standard output
diff --git a/pubspec.yaml b/pubspec.yaml
index 9e8aa0a..88d6678 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: test_process
 version: 1.0.0
-description: A library for testing subprocesses.
+description: A package for testing subprocesses.
 author: Dart Team <misc@dartlang.org>
 homepage: https://github.com/dart-lang/test_process