Remove circular depency in Log::Log4perl::Appender

only require Log::Log4perl::Config if it hasn't already been loaded

Refs #59

Makefile.PL

@@ -46,6 +46,7 @@ WriteMakefile(
     'PREREQ_PM'		=> { Test::More    => 0.45,
                              File::Spec    => 0.82,
                              File::Path    => 2.06_06,
+                             Class::Load   => 0.23
                            }, # e.g., Module::Name => 1.1
     ($] >= 5.005 ?    ## Add these new keywords supported since 5.005
       (ABSTRACT_FROM => 'lib/Log/Log4perl.pm', # retrieve abstract from module

lib/Log/Log4perl/Appender.pm

@@ -6,9 +6,9 @@ use 5.006;
 use strict;
 use warnings;
 
-use Log::Log4perl::Config;
 use Log::Log4perl::Level;
 use Carp;
+use Class::Load qw/is_class_loaded/;
 
 use constant _INTERNAL_DEBUG => 0;
 
@@ -96,6 +96,11 @@ sub new {
 
         #whether to collapse arrays, etc.
     $self->{warp_message} = $params{warp_message};
+
+    if (!is_class_loaded('Log::Log4perl::Config')) {
+        require Log::Log4perl::Config;
+    }
+
     if($self->{warp_message} and
        my $cref = 
        Log::Log4perl::Config::compile_if_perl($self->{warp_message})) {