Uncheck HTML Syntax Validator for PHP Files
Window>Preferences>General>Content Types ---> Text>PHP Content Type
Add *.module and *.install
To have date as an attribute of your nodes: http://drupal.org/project/date
To have master-detail tables: You can use the book module that's already in the core drupal 7.
WYSIWYG text editor: http://drupal.org/project/ckeditor then download http://ckeditor.com/download and unpack it at /sites/all/modules/ckeditor/ckeditor
Views: To add custom forms. It requires ctools