Change .NET framework to 4.0
Merge branch 'master' of https://github.com/Kooboo/CMS
Add the module installation guide and make the possible for developer to do some initializations when the module is installing.
Merge pull request #28 from kooboo-jifeng/4efabe580b22e0c42a5598071deae9ce2d775ed0

Push issue #2