[doc][handbook] Update C++ standard and Dumux version

doc/handbook/0_dumux-handbook.tex

@@ -42,7 +42,7 @@
 % Dune and Dumux logo
 \newcommand{\Dune}{{DUNE}\xspace}
 \newcommand{\Dumux}{\texorpdfstring{Du\-Mu$^\text{x}$\xspace}{DuMuX\xspace}}
-\newcommand{\DumuxVersion}{3.1}
+\newcommand{\DumuxVersion}{3.2-git}
 \definecolor{dumuxYellow}{HTML}{E19417}
 \definecolor{dumuxBlue}{HTML}{0C73CF}
 
@@ -133,7 +133,7 @@ through the Doxygen documentation.
 Well done. What now? \par
 %
 \textit{``How on earth is this going to help me solve my multi-(phase, component,
-	scale, physics) flow and transport problems in porous media systems?''}, you begin to wonder.
+  scale, physics) flow and transport problems in porous media systems?''}, you begin to wonder.
 Don't panic! In order to best ease our prospective users and developers into the
 wonderful \Dumux simulation environment, we've prepared a \Dumux course and extensively-documented examples.
 \input{4_course}

doc/handbook/2_quickinstall.tex

@@ -2,7 +2,9 @@
 For this quick start guide the following software packages are required:
 \begin{itemize}
 \item GitLab client
-\item A standard compliant C++ compiler supporting C++11 and the C++14 feature set of GCC 4.9. We support GCC 4.9 or newer and Clang 3.8 or newer.
+\item A standard-compliant C++17 compiler supporting the C++11/C++14/C++17 features of GCC 7
+(\Dumux $> 3.1$\footnote{\Dumux $\leq 3.1$ only requires the C++11/C++14 feature set of GCC 4.9, e.g. GCC 4.9 or newer and Clang 3.8 or newer}),
+e.g. GCC 7 or newer and Clang 5 or newer.
 \item CMake 2.8.12 or newer
 \item pkg-config
 \item ParaView (to visualize the results)