gstlal_feature_aggregator: fix some typos, modify some wording

gstlal-burst/bin/gstlal_feature_aggregator

@@ -49,13 +49,13 @@ from gstlal.fxtools import utils
 def parse_command_line():
 
     parser = optparse.OptionParser(usage=__usage__, description=__description__)
-    group = optparse.OptionGroup(parser, "Listener Options", "General settings for configuring the listener.")
+    group = optparse.OptionGroup(parser, "Aggregator Options", "General settings for configuring the online aggregator.")
     group.add_option("-v","--verbose", default=False, action="store_true", help = "Print to stdout in addition to writing to automatically generated log.")
     group.add_option("--log-level", type = "int", default = 10, help = "Sets the verbosity of logging. Default = 10.")
     group.add_option("--rootdir", metavar = "path", default = ".", help = "Location where log messages and sqlite database lives")
     group.add_option("--tag", metavar = "string", default = "test", help = "Sets the name of the tag used. Default = 'test'")
     group.add_option("--sample-rate", type = "int", metavar = "Hz", default = 1, help = "Set the sample rate for feature timeseries output, must be a power of 2. Default = 1 Hz.")
-    group.add_option("--processing-cadence", type = "float", default = 0.1, help = "Rate at which the synchronizer acquires and processes data. Default = 0.1 seconds.")
+    group.add_option("--processing-cadence", type = "float", default = 0.1, help = "Rate at which the aggregator acquires and processes data. Default = 0.1 seconds.")
     group.add_option("--request-timeout", type = "float", default = 0.2, help = "Timeout for requesting messages from a topic. Default = 0.2 seconds.")
     group.add_option("--kafka-server", metavar = "string", help = "Sets the server url that the kafka topic is hosted on. Required.")
     group.add_option("--input-topic-basename", metavar = "string", help = "Sets the input kafka topic basename. Required.")
@@ -112,18 +112,18 @@ class StreamAggregator(object):
         ### set up aggregator 
         logger.info("setting up aggregator with backend: %s"%options.data_backend)
         if options.data_backend == 'influx':
-                self.agg_sink = io.influx.InfluxDBAggregator(
-                    hostname=options.influx_hostname,
-                    port=options.influx_port,
-                    db=options.influx_database_name,
-                    reduce_across_tags=False,
-                )
+            self.agg_sink = io.influx.InfluxDBAggregator(
+                hostname=options.influx_hostname,
+                port=options.influx_port,
+                db=options.influx_database_name,
+                reduce_across_tags=False,
+            )
         else: ### hdf5 data backend
-                self.agg_sink = io.hdf5.HDF5Aggregator(
-                    rootdir=options.rootdir,
-                    num_processes=options.num_processes,
-                    reduce_across_tags=False,
-                )
+            self.agg_sink = io.hdf5.HDF5Aggregator(
+                rootdir=options.rootdir,
+                num_processes=options.num_processes,
+                reduce_across_tags=False,
+            )
 
     def fetch_data(self, job_consumer):
         """
@@ -152,7 +152,7 @@ class StreamAggregator(object):
 
     def process_queue(self):
         """
-        process and aggregate features on a regular cadence
+        process and aggregate features from feature extraction jobs on a regular cadence
         """
         if utils.in_new_epoch(aggregator.now(), self.last_save, 1):
             self.last_save = aggregator.now()
@@ -216,6 +216,7 @@ class StreamAggregator(object):
         shut down gracefully
         """
         logger.info('shutting down feature aggregator...')
+        self.is_running = False
 
 class SignalHandler(object):
     """