pthread_array_sum plot: increase title font

Author: cirosantilli

posix/interactive/pthread_array_sum.gnuplot

@@ -3,6 +3,11 @@ set terminal png size 1024, 1024
 set style data linespoints
 set key autotitle columnhead
 set output 'pthread_array_sum.png'
+set title font ",20"
+set xlabel font ",16"
+set ylabel font ",16"
+set lmargin 12
+set bmargin 4
 set title "Array sum time elapsed in function of threads"
 set xlabel "threads"
 set ylabel "time (s)"