revise echo messages of build script

guide_build.sh

-#!/bin/sh
-
-## Avoid the use of shell builtin echo (for -e option)
-alias echo='/bin/echo -e'
+#!/bin/bash
 
 ## Check dependencies
 ##-------------------
@@ -12,15 +9,16 @@ if [ -n "$( ./check_pkg.py sphinx sphinxcontrib.bibtex sphinx_rtd_theme )" ]; th
     exit 2
 fi
 
-echo "\t¤ Clean previous build"
+echo "¤ Clean previous build"
 make clean
 echo
 
-echo "\t¤ Generation of the guide"
+echo "¤ Generation of the guide"
 make html > /dev/null
 echo
 
-echo "\t¤ End of building run"
-echo "Open ./build/html/guide.html"
+echo "¤ End of HTML building"
+echo ""
+echo "open ./build/html/index.html"
 
 exit 0