Better Installation instructions

[IshankGulati]

Installation instructions on opendetection homepage is a bit lacking.

OpenNI is an optional dependency in PCL and OpenCV but opendetection doesn't build without it as it requires BUILD_apps_3d_rec_framework=ON. It should be listed as an additional dependency.

Also, in my case I had to use BUILD_TESTS=ON in VTK 6.3 which is not listed in installation instructions.

Lastly, I am not sure about this one but it also requires VTK and OpenCV to be build with QT.

[Aravind-Suresh]

Also, installation instruction says PCL v1.6+, but v1.6 doesn't have apps in it. The latest version v1.8 or the source has the required apps. This small change should also be added apart from the one mentioned above.

[krips89]

@IshankGulati Thanks for pointing this out. PCL build settings will determine its own dependencies (with all the details including versions) and should not be included here. To address your concern, I have mentioned about OpenNI in the dependency information of PCL, but not as an additional dependency.

Can you specifically point out, what fails without those options in VTK/OpenCV?

@Aravind-Suresh Thanks, I have updated the documentation.

[hanshammel1337]

I think there should be more improvment.
Under PCL 1.8 there is OpenNI mentioned. Obviously there are OpenNI and OpenNI2. Which version is correct?
And in the examples for 3D a kinect camera is used. Again: Which version? Kinect v1 (XBox 360) oder Kinect v2 (Xbox One)? It would be nice when this information were more precise.