- SVG export
- more work on new geo database

Changed default font sizes to 13/16 (fltk/opengl). On recent monitors with
huge resolutions, 12/14 is really small

modified patch from philip kelleners (mostly for irix)

make mouse selection mode a regular option (for Ruth)

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

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

smaller default polyg offset

make "initial mesh only" option visible in scripts

reverting last change: Matthias' fix does not work

trying Matthias Melcher's fix for the delete widget crashes (this fix
does not require to derive our own popup button class)

minimize the number of files that include GmshVersion.h: it's annoying to
recompiletoo many files just because the version string changes

fix popup+make depend

fix cygwin compile

moved most OS-dependent functions in OS.cpp