F left right groovy

mostly a sr_description rework to be more generic and handle left/right, muscle/motor simulated/real hands (transmission different in real but identical for sim), and pst/biotac/ellipsoid/ubi finger tips through arguments. 

all the existing "robots" were taken into account and a both automatic urdf consistency checks and manual visual test in rviw with joint sliders are provided to confirm the generated models are working nice

depends on xacro:if statement (backported from hydro-devel)

some additionnal changes to handle multi hand systems, get rid of unsused packages or remove deprecated use of urdf_test package.