Implement uniform_inside_sphere_distribution extension.

Implement uniform_inside_sphere_distribution extension.

2016-10-26  Edward Smith-Rowland  <3dw4rd@verizon.net>

	Implement uniform_inside_sphere_distribution extension.
	* include/ext/random: Implement uniform_inside_sphere_distribution.
	* include/ext/random.tcc: Ditto.
	* testsuite/ext/random/uniform_inside_sphere_distribution/
	cons/default.cc: New.
	* testsuite/ext/random/uniform_inside_sphere_distribution/
	cons/parms.cc: New.
	* testsuite/ext/random/uniform_inside_sphere_distribution/
	operators/equal.cc: New.
	* testsuite/ext/random/uniform_inside_sphere_distribution/
	operators/generate.cc: New.
	* testsuite/ext/random/uniform_inside_sphere_distribution/
	operators/inequal.cc: New.
	* testsuite/ext/random/uniform_inside_sphere_distribution/
	operators/serialize.cc: New.

From-SVN: r241562