Changes in flowgraph and channel_fsm. Now the number of channels in acquisition mode can be controlled from the config file.

git-svn-id: https://svn.code.sf.net/p/gnss-sdr/code/trunk@179 64b25241-fba3-4117-9849-534c7e92360d

src/core/interfaces/channel_interface.h

@@ -57,6 +57,7 @@ public:
     virtual void start_acquisition() = 0;
     virtual void set_signal(Gnss_Signal) = 0;
     virtual void start() = 0;
+    virtual void standby() = 0;
     virtual void stop() = 0;
 };