Mammoth

* Read children of w:object elements.

* Add support for document transforms.

* Handle hyperlinks created with complex fields.

* Handle absolute paths within zip files. This should fix an issue where some
images within a document couldn't be found.

* Allow style names to be mapped by prefix. For instance:

r[style-name^='Code '] => code

* Add default style mappings for Heading 5 and Heading 6.

* Allow escape sequences in style IDs, style names and CSS class names.

* Allow a separator to be specified when HTML elements are collapsed.

* Add include_embedded_style_map argument to allow embedded style maps to be
disabled.

* Include embedded styles when explicit style map is passed.

* Ignore bold, italic, underline and strikethrough elements that have a value of
false or 0.

* Ignore v:imagedata elements without relationship ID with warning.