Adding calendar conversions from Issue #744

git-svn-id: file:///srv/svn/repos/tudat/trunk@555 ac7aa084-b6da-11df-bf42-7fac39f0224f
Adding Halley root finder; Issue #733

git-svn-id: file:///srv/svn/repos/tudat/trunk@556 ac7aa084-b6da-11df-bf42-7fac39f0224f