Fixed a bug resulting in slight deviation in analytic swaption approximation.

git-svn-id: http://svn.finmath.net/finmath%20lib/trunk@993 48fcbb9e-5639-0410-8b25-842128a4905d
Added unit test for analytic swaption approximation.

git-svn-id: http://svn.finmath.net/finmath%20lib/trunk@994 48fcbb9e-5639-0410-8b25-842128a4905d
Added package description.

git-svn-id: http://svn.finmath.net/finmath%20lib/trunk@995 48fcbb9e-5639-0410-8b25-842128a4905d
Added package description.

git-svn-id: http://svn.finmath.net/finmath%20lib/trunk@996 48fcbb9e-5639-0410-8b25-842128a4905d