Update minimally required version of castle core

Fix Nuget package installs incompatible version of Castle.Core #20

Author: iappert

nuget/Ninject.extensions.Factory.nuspec

@@ -13,7 +13,7 @@
 	<projectUrl>http://www.ninject.org</projectUrl>
     <dependencies>
       <dependency id="Ninject" version="" />
-      <dependency id="Castle.Core" version="[3.0.0.0,4.0.0.0)" />
+      <dependency id="Castle.Core" version="[3.2.0.0,4.0.0.0)" />
     </dependencies> 
   </metadata>
-</package>
+</package>