Added missing word and link

Based on the keypoints found we have to +extract+ features (linked tutorial which explains how features work in pcl)
Dual quaternion transformation estimation algorithm added
dq renamed to dual_quaternion;
tests added
dual quaternion precision changed to double to pass the tests
Remove shared_ptr from param_k_ and param_radius_

fixes segfault im lum
Add an overload of pcl::io::savePNGFile().

The new function takes sensor_msgs::Image and saves it as a PNG file.
Currently supported are "rgb8", "mono8", and "mono16" image encodings.
Add PointCloudImageExtractor base class and several implementations.

* PointCloudImageExtractorFromRGBField produced a color image based on
  the data in "rgb" field of a point cloud.
* PointCloudImageExtractorFromNormalField produced a color image based on
  the data in "normal" field of a point cloud.
* PointCloudImageExtractorFromLabelField produced a mono image based on
  the data in "label" field of a point cloud.
* PointCloudImageExtractorFromZField produces a mono image based on the
  "z" field of a point cloud.
* PointCloudImageExtractorFromCurvatureField produces a mono image based on the
  "curvature" field of a point cloud.
* PointCloudImageExtractorFromIntensityField produces a mono image based on the
  "intensity" field of a point cloud.
Add an overload of pcl::io::savePNGFile().

The new function takes a field name and uses appropriate
PointCloudImageExtractor subclass to extract an image from the given
field. Currently supported are "normal", rgb", "label", "z",
"curvature", and "intensity" fields.
Add pcd2png application to the "tools" module.
Add tests for Point Cloud Image Extractors.
fixed memory leak
whitespaces added to comply with PCL style; small typos fixed
added missing documentation line, fixed typos in documentation
added comment, fixed typo in another comment
added possibility to split row and column jump for iterating over pixels, setTrianglePixelSize still available for setting both equally.
Merge pull request #194 from jspricke/flann_shared_ptr

Remove shared_ptr from param_k_ and param_radius_
Merge pull request #240 from holzers/master

Added PXC Grabber (for Intel Perceptual Computing SDK cameras)
Create README.md
Merge pull request #229 from dirkholz/improved_approx_mesh

Slightly improved approx. meshing by allowing to use different offsets when iterating over rows and columns
typo: s/succesfully/successfully/g