Added the namespace eo for the global variable rng in eoRNG.cpp

Also added "using eo::rng" in eoRNG.h so nothing has to be modified.
We should gradually move to write eo::rng everywhere, and remove that using
directive to be almost full-proofed against possible name collision.

eo/src/utils/eoRNG.cpp

@@ -3,5 +3,8 @@
 
 /// The global object, should probably be initialized with an xor
 /// between time and process_id.
+namespace eo
+{
 eoRng rng((uint32) time(0));
+}