Add doc about enabling other LidarView features such as SLAM

Add doc about enabling more LidarView features which depend on additional external libraries that will be built by superbuild.
Give an example about enabling SLAM support in LidarView, and point to How to SLAM with LidarView tutorial.

Documentation/LidarView_Developer_Guide.md

@@ -13,6 +13,7 @@
     3. [Windows build instructions](#windows-build-instructions)
     4. [Linux dependencies](#linux-dependencies)
     5. [Linux build instructions](#linux-build-instructions)
+    6. [Enabling additional LidarView features](#enabling-additional-lidarview-features)
 3. [Packaging instructions](#packaging)
 4. [Troubleshooting](#troubleshooting)
     1. [Superbuild failure with PCL enabled](#superbuild-failure-with-pcl-enabled)
@@ -118,6 +119,7 @@ Some dependencies, on certain platforms, must be compiled by the superbuild, and
     * You can use absolute or relative path to point to the LidarView source directory, but be sure to adapt its path to the directory created step 2.
     * Should you want to build in RelWithDebInfo mode (in order to attach a debugger for instance), replace "Release" by "RelWithDebInfo".
     * This command should show no errors, else they must be fixed.
+    * To enable additional features, see section [Enabling additional LidarView features](#enabling-additional-lidarview-features).
 
 7. Inside the command prompt, start building by entering:
 
@@ -194,6 +196,7 @@ The following packages are needed to build on Ubuntu 16.04:
 
     * By default the generator used is **make**, if you prefer to use **ninja**, add the option `-GNinja`.
     * Take note that this command mentions the subdirectory "*Superbuild*" inside the source directory and not the source directory itself.
+    * To enable additional features, see section [Enabling additional LidarView features](#enabling-additional-lidarview-features).
 
 4. Start building by entering:
 
@@ -216,6 +219,13 @@ The following packages are needed to build on Ubuntu 16.04:
 
     `git submodule update --init --recursive`
 
+### Enabling additional LidarView features
+
+The command presented in step Windows/6 or Linux/3 enables basic LidarView features, which use basic dependencies.
+To enable more features that rely on additional external libraries, you can use the `ENABLE_<lib>=True` flags. This will download and install the required dependencies, and enable the corresponding LidarView features.
+
+For example, to build LidarView with SLAM support, use `-DENABLE_ceres=True -DENABLE_nanoflann=True -DENABLE_pcl=True -DENABLE_slam=True` (more info in [How to SLAM with LidarView](https://gitlab.kitware.com/keu-computervision/slam/-/blob/master/paraview_wrapping/doc/How_to_SLAM_with_LidarView.md)).
+
 ## Packaging instructions <a name="packaging"></a>
 
 1. Activate the build of tests in the cmake configuration: