Allow pcl to be built against system metslib

This patch allows PCL to build against a system installed metslib
where available.  It uses pkgconfig to try to discover metslib.pc,
and when both are available HAVE_METSLIB is set to ON and the
include paths are modified to use metslib's location as discovered
by pkgconfig.  When pkgconfig and/or metslib is not found, cmake
will continue to use the bundled version of metslib as before.
Whitespace cleanup in registration/CMakeLists.txt

While making modifications for metslib, I noticed that there was
some mixed use of tabs and spaces for intentation.  I normalized
them all to 4 spaces per tab and made the indentation of all of
the "set" blocks consistent.
Code for MomentOfInertia feature class
Tests for MomentOfInertia feature implementation
Tutorial for MomentOfInertia feature class
Code for RoPS feature
Tests for RoPS feature implementation
Tutorial for RoPS feature class
Fixed some warnings
Fixed a bug with the instantiation
Initial push of JointICP
Adding missing cpp file
Texture mapping supports more precise camera model.

Existing behaviour is the default.
Made sure the LICENSE text was identical to the given version
Comply with programming style rules (indentation)
Comply with programming style rules and retain original form of initializer
Bug fix for MomentOfInertia instantiation
Add new parameters to documetation.
Small features: more comfortable thread handling
Merge pull request #370 from mdkus/master

Small features: more comfortable thread handling