add draw_range message
help file with new draw_range message
Merge remote-tracking branch 'avilleret/master'

Conflicts:
	src/Geos/gemvertexbuffer.cpp
proper handling of range message

and initialize it!
linebreaks; parameters to play with...

- turn off rendering of wave by default
- add nbxs for pointsize, osci-length,...
properly detect whether we have an offset or not

the old behaviour was broken for texture_coords, as passing two
tables U&V (which is totally valid), would yield an error (since we
were expecting two values to always be one table + one offset).