upload book attachments, not finished yet
Merge branch 'feature-book' of https://github.com/squallcs12/tangthuvien into feature-book

Conflicts:
	book/features/steps/generate_book_prc_steps.py
	book/features/steps/index_steps.py
	book/features/steps/upload_book_attachments_steps.py
	book/templates/book/_upload_attachment.phtml
	book/templates/book/read.phtml
	book/urls.py
	lettuce_setup/function.py