Fixed issue #874 by ensuring that h_index is never negative (which only appears to happen when distance is exactly 0).
Fix shapes not drawing with VTK6
Minor tutorial fixes
fixing bug of estimating translation vector
Merge pull request #884 from VictorLamoine/local_doc_tutorial_fixes

Minor tutorial fixes
Merge pull request #883 from VictorLamoine/vtk6_fixes

Fix shapes not being drawn with VTK6
Merge pull request #875 from mohawkjohn/issue_874

Fixed issue #874 by ensuring that h_index is never negative
Merge pull request #885 from tttamaki/master

fixing bug of estimating translation vector