modified patch from philip kelleners (mostly for irix)

typo

- add compatibility syntax for getdp (string~{fexpr})
- add possibility to write/append to files with Printf

merging offscreen rendering from branch

make mouse selection mode a regular option (for Ruth)

fixed compil of non-interactive version

- fixed .msh save of negative volume 2nd order hexas

fix info msg

cleanup

new upstream release

need to add new vertices into Surface->Vertices (for possible later extrusions)

make "common" extrusions create surfaces with correct orientations for netgen

shorter label

set node renum=0 by default (weird side effects on some meshes: need to
take closer look)

link with GmshPlugin before GmshCommon (for dave)

add option to renumber the nodes in .msh files (to avoid gaps in the sequence)

fixed indexing bug when the external view and the current view don't have
the same number of time steps

don't use the "manual" numbering the extrude demo: it creates bad habits
for new users

pretty print