Make sure knowrob_objects loaded with knowrob_vis because visualization of semantic map might fails without.
Minor fix for tf frame names without '/' at the beginning of the name. Also set mesh colors to zero so that embedded textures work in rviz and knowrob_vis (Note: tiff format is not supported by the web canvas)
Merge branch 'indigo-devel' of https://github.com/knowrob/knowrob into indigo-devel