Fix bug when trying to save bvh file but skeleton hadn't been loaded.
CloudCluster no longer uses sortstruct

There was no need to use the struct to sort the points in the cloud.
Code is simpler and more efficient now.
Legfitter simplified sortstruct code.

sortsctruct only needs to know about the cloud, not the whole LegFitter class.
Enforced same code style in all includes.
CmakeLists added openmp,PointCloud added ConstPtr, main added other dogs folders.

Cmake compilation was done without openmp support.
PointCloud now uses ConstPtr for pcl cloud inputs.
in main.cpp added folders with other dogs data.
BonePosFinder added method find_leg_lower_3_joints_line_ransac

This method tries to find the leg three lower positions.
It is not giving good results now, but it must be a bug in the code.
Since the ransac method by itself works quite well.
Minor fixes to manual ground truth in MultiCamViewer.

Now it automatically changes mode with set_ground_truth state variable.
BonePosFinder added enum to name the different methods.

Enums are easier to read than integer for a human being so code is easier
to understand now
GroundTruth now loads and saves results on a PCL cloud file.

Using standard formats is better than our own format.
Added few methods to PointCloud class to be able to use it with
two indices.