added storyboard, gifs and swf to 31.3

I renamed some of the storyboard images (31.3) so they all use double-digit
numbering. I also added the swf version of the animation, and two gifs.

In 42.3 news, I changed the MHT rubbish into actual HTML, and will add
functionality to index.php to strip doctype, head tag, etc. from included
HTML files.

I forgot to pull before making all of these changes, so they will be
merged in a minute.
Merge branch 'master' of ssh://github.com:/blieque/btec
added 2.4, made 42.3 html data into actual html,..

I added 2.4, with just a table of computer parts for the assignment. I
need to finish 42.3 and 31.3, and resubmit 31.2 before I can continue
with this one, though.

The *.mht generated by Excel was also a mess (it is an *.mht, I guess),
so I changed it into standard HTML5. I removed the original as a result.

In index.php, I worked on improving the include code, and the conversion
of markdown emphasis, boldening and code in block elements to HTML.
Regex look-arounds came into this, and I now like regex even more. 42.3
has changed as a result of fiddling with including (which is actually
proken ATM).