Add text block tests.
Implement book text block based on ftw.contentpage text block.
Rename paragraphs to textblock in tests and docstrings.
Update block LaTeX to render BookTextBlock instead of Paragraph.
Change validation viewlet to validate new BookTextBlock instead of Paragraph.
Change target release to 3.0.0.
Add upgrade step for replacing Paragraph with BookTextBlock.
Fix BookTextBlock name in GS type xml.
Rename Add Book Text Block permission for consistency.
Merge pull request #51 from 4teamwork/jone-refactor-textblock

Replace Paragraph with BookTextBlock.
Implement tinymce plugin for keywords.
Add book keyword index.
Extend HTML to LaTeX converter to convert index entries.
Implement index in default PDF layout.
Add book_keywords catalog metadata.
Install ftw.tabbedview in development.
Add select2 javascript library.
Add "keywords" tab.
Implement "keywords" tab.
Update English and German translations.