Updating documentation.

SConstruct

@@ -10,7 +10,10 @@ AddOption('--cfg', help='Specify a configuration file (see config.example')
 ##
 configFile = GetOption('cfg')
 if configFile == None:
-	configFile = 'config.example'
+	print '<<ERROR>> You need to specify a configuration file using:'
+	print '<<ERROR>>    scons --cfg [filename]'
+	print '<<ERROR>> Please find example of configuration files in ${ALTA}/configs/scons/'
+	Exit(1)
 #end
 
 if not os.path.exists(configFile):

documents/install.dox

@@ -101,19 +101,13 @@ Using scons, the compilation of ALTA is straightforward:
 
 \verbatim
 $ cd $ALTA
-$ scons -i
+$ scons --cfg [filename] -i
 \endverbatim
 
-This compilation command automatically download the dependencies of ALTA
-core and plugins. If you already have one of the dependencies installed on
-your system, you can use a configuration file in the scons call:
-
-\verbatim
-$ scons --cfg config.file
-\endverbatim
-
-An example of the configuration file is provided at <em>$ALTA/config.example
-</em>.
+You need to provide a system dependant configuration file. You will find
+examples of such configuration files in the <em>$ALTA/configs/scons</em>
+directory.  This compilation command automatically download the dependencies of
+ALTA core and plugins. 
 
 All the resulting elements of ALTA (binaries, dynamic and static libraries)
 are outputted in: <em>$ALTA/sources/build</em> directory. The dependencies

documents/mainpage.dox

@@ -82,12 +82,14 @@ is lightweight and only requires Python to be installed (ALTA uses Python for
 its high level scripting mechanism). To build using scons, go to the root
 directory of ALTA and type:
 \verbatim
- $ scons -i
+ $ scons --cfg [filename] -i
 \endverbatim
 
-This should obtain some of ALTA's dependencies (such as Eigen) and compile the
-main package of the library (i.e. the core, the command line tools, and some
-plugins).
+You need to provide a plateform dependant configuration file. You will find
+examples of such configuration files in the $ALTA/configs/scons directory.
+Running this command should obtain some of ALTA's dependencies (such as Eigen)
+and compile the main package of the library (i.e. the core, the command line
+tools, and some plugins).
 
 To use QMake, or for a more detailed view of ALTA's building scripts and
 dependencies, please refer to \ref install.