update docs and messages for brew cask cat

USAGE.md

@@ -80,6 +80,7 @@ This will both uninstall the Cask and remove symlinks which were created in
 The following commands are for Cask authors:
 
 * `audit` -- verifies installability of Casks
+* `cat` -- dumps the given Cask to the standard output
 * `create` -- creates a Cask and opens it in an editor
 * `edit` -- edits the given Cask
 * `checklinks` -- checks for bad Cask links

doc/src/brew-cask.1.md

@@ -42,6 +42,9 @@ names, and other aspects of this manual are still subject to change.
     Modify Alfred's search scope to include the Caskroom directory where
     Applications are stored.
 
+  * `cat` <Cask>:
+    Dump the given Cask definition file to the standard output.
+
   * `checklinks`:
     Check for bad Cask links.
 

lib/cask/cli/cat.rb

@@ -12,6 +12,6 @@ def self.run(*arguments)
   end
 
   def self.help
-    "display the source of cask."
+    "dump raw source of the given Cask to the standard output"
   end
 end

test/cask/cli/cat_test.rb

@@ -29,7 +29,7 @@ class BasicCask < TestCask
     CLIOUTPUT
   end
 
-  it 'raises an exception when the cask doesnt exist' do
+  it %q{raises an exception when the cask doesn't exist} do
     lambda {
       Cask::CLI::Cat.run('notacask')
     }.must_raise CaskUnavailableError