make cheatsheets column width exactly 57 mm

Notes:
The A4 long dimension is 297 mm. With 2.5 mm left and right margins and
7/4 mm spacing between the 5 columns (4 gaps), this gives
(297 - 2.5*2 - 4*7/4) / 5 = 57 mm wide columns.

Author: jimustafa

cheatsheets.tex

@@ -104,7 +104,7 @@
 \setlength\parindent{0pt}
 \setlength{\tabcolsep}{2pt}
 \baselineskip=0pt
-\setlength\columnsep{0.5em}
+\setlength\columnsep{1.75mm}
 
 
 % --- Macros ------------------------------------------------------------------