Updated JavaDoc.

git-svn-id: http://svn.finmath.net/finmath%20lib/trunk@997 48fcbb9e-5639-0410-8b25-842128a4905d
Added Curve.CurveBuilder (a builder pattern) to build curves.

git-svn-id: http://svn.finmath.net/finmath%20lib/trunk@998 48fcbb9e-5639-0410-8b25-842128a4905d