Update changes.txt

git-svn-id: https://bucket.mit.edu/svn/nilm/zoom@6968 ddd99763-3ecb-0310-9145-efcb8ce7c51f

pcb/zoom/changes.txt

@@ -4,3 +4,9 @@ Changes from r1a:
 * DCR011203U connections are wrong:
   * C45 should go between VREC and PICGND
   * ENABLE should be connected to VREC
+
+- Optocouplers need pullups on the output (reworked with 820 ohms)
+
+- Optocoupler pins 3,4 are reversed
+
+- Document connectors on silkscreen