Remove a harmless warning when compiling

and also when running: metapackages should not contain build dependencies.
Remove multiple pcl::PointCloud <-> sensor_msgs::PointCloud2 conversions
on filtering (~20% faster)
Also adds a voxel grid side parameter to do more or less radical
downsamples
Merge pull request #18 from corot/patch-1

Remove a harmless warning when compiling
Merge pull request #19 from corot/patch-2

Remove multiple pcl::PointCloud <-> sensor_msgs::PointCloud2 conversions
build: avoid hardcoding DepthSense SDK location.

Introduce pkg local Find script, and adjust include and linking
statements to use it.