iOS: add about files and allow scaling when rotate


git-svn-id: https://geuz.org/svn/gmsh/trunk@17969 59c8cabf-10d6-4a28-b43f-3936b85956c4
iOS: fix scaling


git-svn-id: https://geuz.org/svn/gmsh/trunk@17970 59c8cabf-10d6-4a28-b43f-3936b85956c4