install.sh: Fix installing more than 2 fonts

[why]
The implode function can not work correctly because the bash pattern
expansion inserts blanks in unexpected places.

[how]
Use a dump loop instead of being smart.

Fixes: #280

Reported-by: Geoffrey Biggs <gbiggs>
Signed-off-by: Fini Jastrow <ulf.fini.jastrow@desy.de>

install.sh

@@ -138,7 +138,11 @@ implode() {
     # $3... are the elements to join
     local retname=$1 sep=$2 ret=$3
     shift 3 || shift $(($#))
-    printf -v "$retname" "%s" "$ret${*/#/$sep}"
+    while [ $# -gt 0 ]; do
+        ret=$ret$sep$1
+        shift
+    done
+    printf -v "$retname" "%s" "$ret"
 }
 find_include=
 find_exclude=