[hackers] [libzahl] Fix Underfull \hbox in the refsheet || Petr Vaněk

[git]

commit 9177229ec032710501cbb099c2a3de098f2cb51f
Author:     Petr Vaněk <arka...@atlas.cz>
AuthorDate: Sat Apr 30 23:44:43 2016 +0000
Commit:     Mattias Andrée <maand...@kth.se>
CommitDate: Sun May 1 00:14:49 2016 +0200

    Fix Underfull \hbox in the refsheet
    
    The macro \\ should not be used when an empty line follows.

diff --git a/doc/refsheet.tex b/doc/refsheet.tex
index 53b03c5..fbbd7a9 100644
--- a/doc/refsheet.tex
+++ b/doc/refsheet.tex
@@ -6,11 +6,10 @@
 
 
 {\Huge libzahl}
-\\
+\vspace{1em plus .2em minus .1em}
 
 Unless specified otherwise, all times are of type {\tt z\_t}.
-\\ \\
-
+\vspace{2em plus .4em minus .2em}
 
 \begin{tabular}{lll}
 \textbf{Initialisation}       & {}                         & {}                
                                \\