merge revision(s) 39384,39509,39511: [Backport #7961]

	* lib/rexml/document.rb (REXML::Document.entity_expansion_text_limit):
	  new attribute to read/write entity expansion text limit.  the default
	  limit is 10Kb.

	* lib/rexml/text.rb (REXML::Text.unnormalize): check above attribute.

	* lib/rexml/document.rb: move entity_expansion_limit accessor to ...

	* lib/rexml/rexml.rb: ... here to make rexml/text independent from
	  REXML::Document. It causes circular require.

	* lib/rexml/document.rb (REXML::Document.entity_expansion_limit):
	  deprecated.

	* lib/rexml/document.rb (REXML::Document.entity_expansion_limit=):
	  deprecated.

	* lib/rexml/text.rb: add missing require "rexml/rexml" for
	  REXML.entity_expansion_limit.
	  Reported by Robert Ulejczyk. Thanks!!! [ruby-core:52895] [Bug #7961]

	* lib/rexml/document.rb: move entity_expansion_text_limit accessor to ...

	* lib/rexml/document.rb (REXML::Document.entity_expansion_text_limit):

	* lib/rexml/document.rb (REXML::Document.entity_expansion_text_limit=):
	  REXML.entity_expansion_text_limit.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8_7@40812 b2dd03c8-39d4-4d8f-98ff-823fe69b080e