removed clscale & perspective buttons from status bar

use serendipity tetrahedron and haxahedron to compute high order interior vertices (instead of "unusual"... and now inexistant face-saturated incomplete element)

clean up high order routines by refactoring high-order tet/hex/prism/pyram generation code

allow multiple view selection in option window + changed "link" logic to make it much easier to modify options for several views at once

* New version of Trevor Strickler's QuadTri patch (+ examples in benchmarks/extrude_quadtri)

* First pass at SU2 mesh export