Plane surfaces are now recognized and the
usual gmsh "cross" is drawn correctly

occ dvlpt

occ work

fix surfperiodic

more occ work

more occ work

:i

occ work

more occ work

occ work

start opencascade integration

hide entities by clicking on them

added getNumPrimaryVertices (num vertices for a first-order element)

- routines added for finding all or some of an elements neighbours
- many miscellaneous changes and some reorganization

finish Mesh>Edit>Delete

polish gui for navy demonstrator

make Mesh>Delete and Inspect more robust (allowing to change mesh
by other callbacks while in selection mode)

new Mesh>Inspect to get individual ele info

more mesh edit work

small optim

fix labels

much faster element deletion algorithm