Simplify and clean up library literals.

Simplify and clean up library literals.

2013-06-07  Ed Smith-Rowland  <3dw4rd@verizon.net>

	Simplify and clean up library literals.
	* include/std/chrono: Simplify namespace and versioning management.
	* include/bits/basic_string.h: Ditto.
	* testsuite/20_util/duration/literals/types.cc: Remove bogus comment.
	* testsuite/20_util/duration/literals/values.cc: Ditto.
	* testsuite/21_strings/basic_string/literals/types.cc: Ditto.
	* testsuite/21_strings/basic_string/literals/values.cc: Ditto.

From-SVN: r199861