Created custom telemetry packet report

Modeled off of the PositionReport class, I created a TelemetryReport and
used similar serialization to create a working packet that was uploaded to
aprs.fi for testing.

aprslib/packets/__init__.py

@@ -1 +1,2 @@
 from aprslib.packets.position import PositionReport
+from aprslib.packets.telemetry import TelemetryReport

aprslib/packets/telemetry.py

@@ -0,0 +1,32 @@
+from aprslib.packets.base import APRSPacket
+
+class TelemetryReport(APRSPacket):
+    format = 'raw'
+    sequenceno = 0
+    analog1 = 0
+    analog2 = 0
+    analog3 = 0
+    analog4 = 0
+    analog5 = 0
+    digitalvalue = ['0']*8
+    comment = ''
+
+    def _serialize_body(self):
+        # What do we do when len(digitalvalue) != 8?
+        self.digitalvalue = ''.join(self.digitalvalue)
+
+        body = [
+            'T#',  # packet type
+            str(self.sequenceno).zfill(3),
+            str(self.analog1).zfill(3),
+            str(self.analog2).zfill(3),
+            str(self.analog3).zfill(3),
+            str(self.analog4).zfill(3),
+            str(self.analog5).zfill(3),
+            str(self.digitalvalue),
+            self.comment,
+        ]
+        tmpbody = ",".join(body)
+
+        # remove static but erroneous comma between T# and sequenceno
+        return tmpbody[:2] + tmpbody[3:]