Configure figwheel's logging

Figwheel logs in an unusal way, this reconfigure's it to be more
sensible.  In particular, this reduces the verbosity significantly.

lib.app.dev/src/dev_extras.clj

@@ -13,6 +13,16 @@
 (SLF4JBridgeHandler/removeHandlersForRootLogger)
 (SLF4JBridgeHandler/install)
 
+(when (try
+        (require 'figwheel.main.logging)
+        true
+        (catch Throwable _))
+  ;; Undo default logger being extremely fine grained in figwheel,
+  ;; in order to configure figwheel to delegate to slf4j.
+  (let [l @(resolve 'figwheel.main.logging/*logger*)]
+    ((resolve 'figwheel.main.logging/remove-handlers) l)
+    (.setUseParentHandlers l true)))
+
 (defmacro ^:private proxy-ns
   [ns & vars]
   (cons `do

lib.logging.dev/src/logback.xml

@@ -112,6 +112,12 @@
     <appender-ref ref="APP_LOG_FILE" />
   </logger>
 
+  <!-- figwheel puts some useful warnings through as INFO rather than WARN
+       See: https://github.com/bhauman/figwheel-main/issues/130
+       -->
+  <logger name="figwheel.logg" level="INFO">
+    <appender-ref ref="CONSOLE" />
+  </logger>
 
   <!-- Make java.util.logging more efficient at disabled levels.
        See http://logback.qos.ch/manual/configuration.html#LevelChangePropagator -->