add free example

bindings/python/examples/free.py

@@ -0,0 +1,21 @@
+import os, sigar;
+
+sg = sigar.open()
+mem = sg.mem()
+swap = sg.swap()
+sg.close()
+
+print "\tTotal\tUsed\tFree"
+
+print "Mem:\t",\
+    (mem.total() / 1024), \
+    (mem.used() / 1024), \
+    (mem.free() / 1024)
+
+print "Swap:\t", \
+    (swap.total() / 1024), \
+    (swap.used() / 1024), \
+    (swap.free() / 1024)
+
+print "RAM:\t", mem.ram(), "MB"
+