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
Removed check for source normals, since only the target cloud is required to have normals.
Fixed MSVC linker crash.

* Linking pcl_features hit 4GB memory limit in release mode. Disabled whole program optimization and link-time code generation as a workaround.
Corrected initial traversal index

Initial index was wrong when multiple viewports are active.
Add: support IFS file format
Merge pull request #345 from jakobwilm/transformation_estimation_fix

Removed check for source normals
Merge pull request #350 from kwaegel/msvc_linker_fix

Fixed MSVC linker crash.
Made sure the LICENSE text was identical to the given version
Merge pull request #354 from nizar-sallem/ifs_support

Add: support IFS file format