Docx Reader: Added Default instances and removed withDState

Signed-off-by: Jesse Rosenthal <jrosenthal@jhu.edu>
Docx reader: Split math out into math module.

Could use some cleanup, but this is the first step for getting
an OMML reader into TeXMath.
OMath module: Add new file.
Docx reader: Handle inline drawings.

Previous drawings that were under some other toplevel run (i.e., a
hyperlink) wouldn't be properly handled. This should fix that.
Docx reader: Test inline image code.
Merge pull request #1495 from jkr/inline-drawings

Docx reader: Inline image fix
Merge pull request #1494 from jkr/math-module

Math module
Merge pull request #1496 from mpickering/master

Org Writer: Write anchor elements
EPUB Reader: Removed incorrectly set raw parsing options
Updated EPUB tests