Resolve "Add libfontconfig & libfontconfig-dev to Qt dependencies on Linux"

What does this MR do?

Closes #16 (closed), add libfontconfig1 & libfontconfig1-dev has linux requirements in documentation.

Installation/src/LinuxInstall.rst

 Installation for Linux
 ======================
 
-Prerequisites 
+Prerequisites
 ---------------
 
 If not already installed:
@@ -26,13 +26,13 @@ Depending on which linux distribution you use, for example on **Debian/Ubuntu/Mi
         # ~/.bashrc
         export PATH=/home/login/software/cmake/bin:$PATH
 
-Few basic development libraries need to be installed first: ``zlib``, ``iconv``, ``jpeg``, ``png``, ``tiff``, ``freetype``, ``libxml``, ``expat``, and ``icu``. On **Mint 18.x** for instance, you can install them using the following command : 
+Few basic development libraries need to be installed first: ``zlib``, ``iconv``, ``jpeg``, ``png``, ``tiff``, ``freetype``, ``fontconfig``, ``libxml``, ``expat``, and ``icu``. On **Mint 18.x** for instance, you can install them using the following command :
 
 .. code:: bash
 
     $ sudo apt-get install libz3-dev libiconv-hook-dev libpng12-dev \
       libjpeg-turbo8-dev libtiff5-dev libfreetype6-dev libxml2-dev \
-      libexpat1-dev libicu-dev
+      libexpat1-dev libicu-dev libfontconfig1-dev
 
 Next, we also need to install specific development libraries for **Qt**. These requirements are detailed here:
 
@@ -58,7 +58,7 @@ Now you can compile the FW4SPL dependencies with make in the console, it will au
     $ cd Dev\BinPkgs\Build\Debug
     # Adjust the number of cores depending of the CPU cores and the RAM available on your computer
     $ make -j4 install
-    
+
 .. include:: CommonSrc.rst
 
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