Merge branch 'feature/docu-improve-installation-notes' into 'master'

Feature/docu improve installation notes

See merge request tools/frackit!180

README.md

@@ -167,7 +167,7 @@ modules that are not needed, set the corresponding cmake variables
 BUILD_MODULE_ApplicationFramework=0
 BUILD_MODULE_DataExchange=0
 BUILD_MODULE_Draw=0
-BUILD_MODULE_Visualization=0 
+BUILD_MODULE_Visualization=0
 ```
 
 for the configuration step of [OpenCASCADE][2]. For instance, after you downloaded the
@@ -221,30 +221,12 @@ cmake ../
 ```
 
 If cmake cannot find your installation of [OpenCASCADE][2], you probably installed it
-into a non-standard location. In this case, you can define __HINTS__ for cmake to search
-for it. In particular, you would have to change the line
+into a non-standard location. In this case, tell cmake your installation folder by
+setting the variable `OCC_INSTALL_DIR`:
 
-```cmake
-find_path(OCC_INC "Standard_Version.hxx" PATH_SUFFIXES opencascade include/opencascade)
-```
-
-to
-
-```cmake
-find_path(OCC_INC "Standard_Version.hxx" HINTS MY_OCC_INCLUDE_FOLDER)
-```
-
-in the _CMakeLists.txt_ file of the top folder of Frackit, substituting
-MY_OCC_INCLUDE_FOLDER with the path to the source files of [OpenCASCADE][2]
-on your system. The same has to be done for the required packages of
-[OpenCASCADE][2], i.e. in the line
-
-```cmake
-find_library(OCC_LIB ${OCC}
-             PATH_SUFFIXES lib ${OCC_SYS_NAME}/lib ${OCC_SYS_NAME}/vc8/lib)
+```sh
+cmake -DOCC_INSTALL_DIR=PATH_TO_YOUR_OCC_INSTALLATION ../
 ```
-
-you can define HINTS for cmake to find your installation folder of [OpenCASCADE][2].
 Once cmake finished successfully, you could now compile the class documentation:
 
 ```sh