Add media tag with automatic base64 encoding of image files

Added a media tag which enables any passages with the media tag to be parsed
for the filenames of image files, which will then be automatically loaded,
base64 encoded, and embedded within the output html file. This basically means
that it is quite simple to have images contained within stories but still
keeping the simplicity of a single html story file containing the entire story.
There are some restrictions to keep in mind though as IE doesn't have very
proper support, only being supported in IE8 and above, and in that version,
having a 32k file size limit for the encoded data. Later IE versions do not
have this limitation.
Add font (.woff) support to base64 media encoding

Add encoding support for the .woff font format. This was chosen as it seems to
be the most compatible between browsers, without adding many different font
types that will just make the output file larger with minimal gains. This is
put into a for loop in case in the future further font types are needed.
Add audio support(ogg and mp3) to automatic base64 encoding

Added one further media type to the automatic media embedding. The ogg and mp3
formats were chosen, as they are compatible with most browsers. There seems to
be performance issues in some browsers doing it this way, so it's included
primarily for completeness sake more than anything.
Look for Media files in source directory rather than output directory

Rather than looking in the output directory for the files to base64 encode,
look within the source directory. Uses the same sort of code that the
StoryIncludes uses, which necessitated bringing the save directory down the
function chain to the encode text function. Not the cleanest solution for the
problem, but the only one that seemed to be feasible without changing a large
amount of code. Also added in the tags into the encode text function
declaration, as it was forgotten.