* lib/json/editor.rb: be a bit more robust while loading data.
* ext/json/ext/{generator,parser}/extconf.rb:
add a have_header directive for st.h
* test/json: fix some tests.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@12456 b2dd03c8-39d4-4d8f-98ff-823fe69b080e