Bugfixes for more word doc formatting issues

[jacqui]

Closes #379

Test using version #108 of the code and the "Copy of BBG Top5Influential Hip Hop Artists" document. I just setup a test case setup for this combination in the script editor for ya.

Fixes include:

• finding all images, which are turned into top-level elements alongside other main element types (blockquote, embed, list, text)
• correct blockquote treatment
• fake "header" text (bold/underlined)
• trailing & leading whitespace in rendered articles (front-end change - https://github.com/news-catalyst/next-tinynewsdemo/pull/983)