Merge pull request #542 from fnoble/v20_release_notes

v0.20 release notes

RELEASE-NOTES.md

@@ -3,6 +3,7 @@ Piksi Firmware Release Notes
 
 Contents
 --------
+ * [v0.20](#v0.20)
  * [v0.19](#v0.19)
  * [v0.18](#v0.18)
  * [v0.17](#v0.17)
@@ -15,6 +16,23 @@ Contents
  * [v0.10](#v0.10)
  * [v0.8](#v0.8)
 
+v0.20 <a name="v0.20"></a>
+-----
+
+#### Core
+ * Updates to libsbp for stability
+  * Deprecate MSG_PRINT in favor of MSG_LOG which includes log level in protocol
+  * Remove strings that indicate log levels from msg print prefixes
+  * Update the following messages in order to widen PRN field and rename to SID
+    * SBP_MSG_TRACKING
+    * SBP_MSG_ACQ_RESULT
+    * SBP_MSG_OBS
+    * SBP_MSG_EPHEMERIS
+    * SBP_MSG_TRACKING_STATE
+ * Add sanity check for user entered base station position upon broadcast of location
+ * Change tracking threshold to 31 db-hz to help maintain track
+ * Fix known bug where Piksi could operate incorrectly during GPS week rollover
+
 v0.19 <a name="v0.19"></a>
 -----