For places in the revised API where we use lager_event as a default value, use a macro instead

include/lager.hrl

@@ -17,6 +17,7 @@
 
 -define(DEFAULT_TRUNCATION, 4096).
 -define(DEFAULT_TRACER, lager_default_tracer).
+-define(DEFAULT_SINK, lager_event).
 
 -define(LEVELS,
     [debug, info, notice, warning, error, critical, alert, emergency, none]).

src/lager.erl

@@ -83,7 +83,7 @@ md(_) ->
 
 
 dispatch_log(Severity, Metadata, Format, Args, Size) when is_atom(Severity)->
-    dispatch_log(lager_event, Severity, Metadata, Format, Args, Size).
+    dispatch_log(?DEFAULT_SINK, Severity, Metadata, Format, Args, Size).
 
 -spec dispatch_log(atom(), log_level(), list(), string(), list() | none, pos_integer()) ->  ok | {error, lager_not_running}.
 %% this is the same check that the parse transform bakes into the module at compile time
@@ -336,7 +336,7 @@ set_loglevel(Sink, Handler, Ident, Level) when is_atom(Level) ->
 %% @doc Get the loglevel for a particular backend on the default sink. In the case that the backend
 %% has multiple identifiers, the lowest is returned.
 get_loglevel(Handler) ->
-    get_loglevel(lager_event, Handler).
+    get_loglevel(?DEFAULT_SINK, Handler).
 
 %% @doc Get the loglevel for a particular sink's backend. In the case that the backend
 %% has multiple identifiers, the lowest is returned.

src/lager_config.erl

@@ -45,10 +45,10 @@ new() ->
     ok.
 
 get(Key) ->
-    get(lager_event, Key, undefined).
+    get(?DEFAULT_SINK, Key, undefined).
 
 get(Key, Default) ->
-    get(lager_event, Key, Default).
+    get(?DEFAULT_SINK, Key, Default).
 
 get(Sink, Key, Default) ->
     try
@@ -64,8 +64,7 @@ get(Sink, Key, Default) ->
     end.
 
 set(Key, Value) ->
-    set(lager_event, Key, Value).
+    set(?DEFAULT_SINK, Key, Value).
 
 set(Sink, Key, Value) ->
     ets:insert(?TBL, {{Sink, Key}, Value}).
-