support Markdown.pl in bashblog folder. Close #113

bb.sh

@@ -148,7 +148,7 @@ global_variables() {
 
     # Markdown location. Trying to autodetect by default.
     # The invocation must support the signature 'markdown_bin in.md > out.html'
-    markdown_bin=$(which Markdown.pl || which markdown)
+    [[ -f Markdown.pl ]] && markdown_bin=./Markdown.pl || markdown_bin=$(which Markdown.pl 2>/dev/null || which markdown 2>/dev/null)
 }
 
 # Check for the validity of some variables