Timeout::TimeoutError does not exist, use Timeout::Error instead

Also added a require for 'timeout' that contains this code.  Easy to get
confused as there is an alias TimeoutError:

irb(main):001:0> require 'timeout'
=> true
irb(main):002:0> TimeoutError
=> Timeout::Error
irb(main):003:0> Timeout::Error
=> Timeout::Error
irb(main):004:0> Timeout::TimeoutError
NameError: uninitialized constant Timeout::TimeoutError
        from (irb):4

lib/couchrest/monkeypatches.rb

@@ -1,5 +1,6 @@
 require File.join(File.dirname(__FILE__), 'support', 'class')
 require File.join(File.dirname(__FILE__), 'support', 'blank')
+require 'timeout'
 
 # This file must be loaded after the JSON gem and any other library that beats up the Time class.
 class Time
@@ -38,7 +39,7 @@ if RUBY_VERSION.to_f < 1.9
           if IO.select([@io], nil, nil, @read_timeout)
             retry
           else
-            raise Timeout::TimeoutError
+            raise Timeout::Error
           end
         end
       else