[scautopick] cannot process historical data (closed station)

[luca-s]

Fix issue #123 : scautopick fails to detect picks on historical data. The issue happens if the station is closed and if the bindings do not provide a fixed channel (detectStream contains 2 characters, so it relies on SeisComP to find the vertical component) and the sensor doesn't have a Z component.

[luca-s]

A couple of comments.

1. Since I moved the scanning of epochs before the selection of the detection channel, the logs order has changed (just logs, no change in behaviour). Previously you would see something like this:

12:04:37 [info] Adding detection channel 8R.F2901..KPZ
12:04:37 [debug] Adding data channel 8R.F2901..KP1
12:04:37 [debug] Adding data channel 8R.F2901..KP2

Now you get the following instead:

12:05:50 [debug] Adding data channel 8R.F1901..KP1
12:05:50 [debug] Adding data channel 8R.F1901..KP2
12:05:50 [debug] Adding data channel 8R.F1901..KPZ
12:05:50 [info] Adding detection channel 8R.F1901..KPZ

2. Also I did quite some refactoring. If you prefer me to minimize the changes and avoid refactoring, just let me know and I will update the PR by removing the following part.

		const string& cfgNet = it->first.first;
		const string& cfgSta = it->first.second;
		const string& cfgLoc = it->second.locationCode;
		const string& cfgCha = it->second.channel;

		auto addDataChannel = 
			[this, cfgNet, cfgSta, cfgLoc, &subscribeStreams](const string & cha) {
				string streamID = cfgNet + "." + cfgSta + "." + cfgLoc + "." + cha;
				if ( subscribeStreams.find(streamID) == subscribeStreams.end() ) {
					SEISCOMP_DEBUG("Adding data channel %s", streamID.c_str());
					recordStream()->addStream(cfgNet, cfgSta, cfgLoc, cha);
					subscribeStreams.insert(streamID);
				}
		};