Merge pull request #2 from acheetham/FLOE-215

FLOE-215: Add media overlay
FLOE-228: First pass at restructuring the repo to support manually building the EPUB.
The output still has some errors on validation, but seems to work fine in readers.
FLOE-228: Start updating readme to reflect new hierarchy
FLOE-228: Changes to fix validation errors.
FLOE-228: Fixes to README and delta symbol
Merge pull request #3 from acheetham/FLOE-228

FLOE-228: Restructure repository to support manually building the EPUB