Fix a bug in RegionGrowing with oversized output cluster vector.

The clusters vector output by RegionGrowing<PointT, NormalT>::extract()
function was not properly trimmed after filtering out clusters that are
too small and too large. As a result many dozens/hundreds of zero-sized
clusters seeped into the output vector.
Added vtkPolyLine.h header to example_supervoxels.cpp

In 1.7.0 the supervoxel example doesn't build with Visual Studio 2012 (and others: https://github.com/PointCloudLibrary/pcl/issues/202).
Only build pcd_select_object_plane.cpp when QHull is available

As pcd_select_object_plane.cpp requires QHull it should be excluded when QHull is not found.
Check to only build in_hand_scanner when OpenNI is available
Switched from gl.h to qgl.h
Merge pull request #211 from henningpohl/patch-6

Switching from gl.h to qgl.h
Merge pull request #208 from henningpohl/patch-3

Check to only build in_hand_scanner when OpenNI is available
Merge pull request #207 from henningpohl/patch-2

Only build pcd_select_object_plane.cpp when QHull is available
Merge pull request #206 from henningpohl/patch-1

Added vtkPolyLine.h header to example_supervoxels.cpp
Merge pull request #205 from taketwo/region-growing-fix

Fix a bug in RegionGrowing with oversized output cluster vector.
Removed compiler options resulting in a D8021 compiler error in Visual Studio 2012
Merge pull request #214 from henningpohl/patch-1

Removed compiler options resulting in a D8021 compiler error in Visual Studio 2012
Changed the doc to be more sensible
Reduced the normal estimation radius from 0.015 to 0.01, which gives better FPFH features and higher robustness
Introduced further hypothesis pruning by avoiding verification of already accepted polygons
Set the error metric to standard inlier MSE
Use __SSE__ instead of HAVE_SSE_EXTENSIONS
Merge pull request #212 from andersgb1/sample_consensus_prerejective

Fixed a small problem with the alignment prerejective (tutorial) code
Fix more "Parse error at BOOST_JOIN" when moc-qt4
Add note about PCL_NO_PRECOMPILE when adding a custom ptype

Fixing indention while at it.