Fix dynamic settings with falsy values

Author: ebeigarts

lib/settingslogic.rb

@@ -158,7 +158,7 @@ def create_accessors!
   # http://bmorearty.wordpress.com/2009/01/09/fun-with-rubys-instance_eval-and-class_eval/
   def create_accessor_for(key, val=nil)
     return unless key.to_s =~ /^\w+$/  # could have "some-setting:" which blows up eval
-    instance_variable_set("@#{key}", val) if val
+    instance_variable_set("@#{key}", val)
     self.class.class_eval <<-EndEval
       def #{key}
         return @#{key} if @#{key}

spec/settingslogic_spec.rb

@@ -126,6 +126,18 @@ class NoSource < Settingslogic; end
     Settings.language['some-dash-setting#'].should == 'dashtastic'
   end
 
+  it "should handle settings with nil value" do
+    Settings["flag"] = true
+    Settings["flag"] = nil
+    Settings.flag.should == nil
+  end
+
+  it "should handle settings with false value" do
+    Settings["flag"] = true
+    Settings["flag"] = false
+    Settings.flag.should == false
+  end
+
   it "should support instance usage as well" do
     settings = SettingsInst.new(Settings.source)
     settings.setting1.setting1_child.should == "saweet"