solve a show isue from the last commit ( network as a multidigraph)
Merge remote-tracking branch 'pylayers/master'
first work to glue r3d with CIR
get correct slab into array
T and R evaluation ok
remove class Ray2d
Merge branch 'inter' of https://github.com/niamiot/pylayers into niamiot
B R and T are ok.
todo :
evaluate CIR from I
calculation of 2x2 matrix M
Merge remote-tracking branch 'bernard/devel' into inter2

Conflicts:
	pylayers/antprop/rays.py
1st time ever full python raytracing
remains some bugs...
matrix M working
merging nicolas inter branch
dimension problem in fillinter (size of B modified)
 status before Nicolax email
add __repr__ in bsignal.py
add a __repr__ on Rays
add __repr__ in GrRayTud raysc
full python ray tracing done
need some further test to valide
 commit before switching branch