Modifications to try and get EPUB3 basic multimedia support working in newer version of pressbooks.
Merge remote-tracking branch 'upstream/master' into dev
resolves a call to undefined function
Merge pull request #1 from bdolor/epub3

resolves a call to undefined function
Merge remote-tracking branch 'upstream/dev' into dev
Changed the file extentions for book pages from html to xhtml.
Modified OPF template guide element with updates from Epub201 and changed file extentions
The file-as attribute in OPF failed epub 3 validation. Modified to conform to epub3 standards
initial mods to extend class epub201
handing back more functions to the parent class
modified images directory to assets, handed back more functions to parent
Merge pull request #21 from bdolor/epub3

handing back more functions to the parent class
Merge pull request #22 from bdolor/epub3

modified images directory to assets, handed back more functions to paren...
allowing uploads of mimetypes for audio/video
Merge pull request #23 from bdolor/epub3

allowing uploads of mimetypes for audio/video
fixing careless mistake
Merge pull request #24 from bdolor/epub3

fixing careless mistake, or why writing code while at a conference is a bad idea.
verifying media types function
renamed directories for epub output, new sanitize function
Merge pull request #25 from bdolor/epub3

Epub3