[geometry] Added real-life testcase for simplify

git-svn-id: http://svn.boost.org/svn/boost/trunk@86549 b8fc166d-592f-0410-95f2-cb63ce0dd405
Fixes for digamma and zeta based on bug reports by Rocco Romeo.

git-svn-id: http://svn.boost.org/svn/boost/trunk@86550 b8fc166d-592f-0410-95f2-cb63ce0dd405