[graphics/ros-ivcon] Import ros-ivcon-0.1.4

ivcon is a mesh conversion utility.
[graphics] Import ros-convex-decomposition-0.1.9

convex_decomposition contains the Convex Mesh Generation Library, by
John Ratcliff. This library is used to auto-generate convex decomposed
meshes for collision and visualization of robot links.

ROS package that wraps (with some patches) the original project:
http://www.amillionpixels.us/ConvexDecomposition.zip
[devel/ros-xacro] Import ros-xacro-1.7.3

Xacro is an XML macro language. With xacro, you can construct shorter
and more readable XML files by using macros that expand to larger XML
expressions.
[graphics/ros-robot-model] Force the export of tinyxml flags

This fixes compilation issues of packages which depend on robot_model.