Merge pull request #1 from donovankeith/master

Fixed some slight grammar issues, added docstrings to iter-hierarchy.
removed newline after license block, removed seealso tag since its empty. Removed description of the 'file' tag in README as we won't use it. Added description of 'links' tag to README.
updated README file-header example to Python code, Added choices for the level tag. Updated tags
renamed perstistent-data-dialog.pyp to todo-list.pyp, persistent-data is now a tag
Merge pull request #3 from PluginCafe/donovan-keith

Donovan Keith's Todo List example
Fixed active/cached-doc comparison to actually compare the documents. Fixed a bug where the dialog would try to update when cinema was first booting and couldn't find any living active documents.