tuple: Mark more constructors constexpr.

tuple: Mark more constructors constexpr.

2011-08-03  Benjamin Kosnik  <bkoz@redhat.com>

	* include/std/tuple: Mark more constructors constexpr.
	* testsuite/20_util/tuple/cons/constexpr.cc: Split into and extend as:
	* testsuite/20_util/tuple/cons/constexpr-2.cc: ...this.
	* testsuite/20_util/tuple/cons/constexpr-3.cc: ... and this.
	* testsuite/20_util/weak_ptr/comparison/cmp_neg.cc: Adjust line numbers.

2011-08-03  Benjamin Kosnik  <bkoz@redhat.com>
	    François Dumont  <francois.cppdevs@free.fr>

	* testsuite/23_containers/array/at_neg.cc: Move...
	* testsuite/23_containers/array/at.cc: ...here. Remove
	-fno-exceptions, call const at member function.

Co-Authored-By: François Dumont <francois.cppdevs@free.fr>
From-SVN: r177299