Update SCons compilation instructions in README.md, and improve 'scons -c' procedure.

README.md

@@ -35,11 +35,15 @@ depending on whether your shell is bash or csh.
     make
 
 ### Compiling with scons
-    python ./podd/scons/scons.py
+    scons
+
+### Additional SCons features 
 To do the equivalent of "make clean", do
-`python ./podd/scons/scons.py -c`
+`scons -c`
+To compile with debug capabilities, do
+`scons debug=1`
 To compile the standalone codes the are part of podd, do
-`python ./podd/scons/scons.py standalone=1`
+`scons standalone=1`
 
 Running
 -------

src/SConscript.py

@@ -46,6 +46,9 @@ try:
 except:
 	print " Continuing ... "
 
+Clean(srclib,cleantarget)
+Clean(srclib,localmajorcleantarget)
+
 #baseenv.Install('../',srclib)
 #baseenv.Alias('install',['../'])