fix typo (#26)

Author: dastrobu

README.md

@@ -7,7 +7,7 @@
 Command line argument parser package in Swift.
 
 The basic idea is to define a tree structure of parsers which then parses all command line arguments.
-This approach is very flexible and allows for quick and easy flag parsing for a simple scirpt, as well as 
+This approach is very flexible and allows for quick and easy flag parsing for a simple script, as well as 
 complicated parse trees for big command line programs.
 
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