Remove 'Object#send!'

'Object#send!', as defined in active_support/core_ext/object/misc.rb, was originally added because Ruby 1.9 has such a method as well. Object#send! has been removed from Ruby 1.9 since November 2007.

Furthermore, using 'Object#send!' can break Delegate classes such as Tempfile, though it depends on the load order. Delegate delegates all methods to its underlying object. If Object#send! is defined before Tempfile was defined, then Tempfile will think that its underlying File object has a 'send!' method. Thus, calling Tempfile#send!(:size) will result in Tempfile calling File#send!(:size). File#size doesn't exist, so a crash will occur as a result. What should have happened is that Tempfile#size is called. But since Object#send! was defined before Tempfile was defined, Tempfile (or rather, Delegate) will override 'send!' and replace it with a version that forwards the call to File.

The attached patch removes 'Object#send!'.