Merge pull request #54 from carlosalberto/master

Implement  shouldTerminateAfterLastWindowClosed bits ;)
initial String.prototype.match support, calling @@match.  do most of the implementation in RegExp.  also, rename String.prototype.contains to String.prototype.includes
more regexp symbol prototype methods.  also add Regexp.prototype.flags getter
add Symbol.split and Symbol.search, along with (unimplemented) regexp methods
moar tests (for RegExp.prototype.flags and +0/-0 in Map/set)
+0/-0 fixes
update string-contains.js to use String.prototype.includes
add test for classes being block scoped from kangax's table
more s/contains/includes
fix compiler error in stage0
enable Reflect.{ownKeys,preventExtensions}
add support for anonymous classes, and also for class expressions to appear in the 'extends' clause.
add es5-compat-table's test for an (anon) class defined in the 'extends' clause.  ugh :)
switch back to previously spec'ed algorithms until the spec bugs are fixed in the next rev