Mirror raw sensor temp through when the controller isn't configured yet

is_configured() (Smith's model plant params, only ever set once a Sud
loads) gates TcTask's call to tc.process() - the only place theta_ist/
heatrate_ist/heatrate_soll get updated and broadcast. Right after
server start, before any Sud has ever loaded, that left them frozen at
their __init__ defaults forever, so the GUI's Ist Temp/Rate and Soll
Rate displays never showed anything on connect. Mirror the raw sensor
reading through instead, with rates at 0 since there's no controller
output yet.

tasks/tempctrl.py

@@ -78,5 +78,19 @@ class TcTask(ATask):
 			# would otherwise raise.
 			if self.tc.is_configured():
 				self.tc.process()
+			else:
+				# Smith's model plant params only ever arrive from a Sud's
+				# doc (see brewpi.py), so right after server start - before
+				# any Sud has ever loaded - is_configured() stays False and
+				# process() never runs. Without this, theta_ist/
+				# heatrate_ist/heatrate_soll (and thus the 'Ist'/'Soll'
+				# messages below) would stay frozen at their __init__
+				# defaults forever, leaving the GUI's Ist Temp/Rate and
+				# Soll Rate displays blank on connect. Mirror the raw
+				# sensor reading straight through instead - there's no
+				# controller output yet to report a real rate for.
+				self.tc.theta_ist = self.tc.get_theta_ist_set()
+				self.tc.heatrate_ist = 0.0
+				self.tc.heatrate_soll = 0.0
 			await asyncio.sleep(self.interval)