HTML Changes

Fixes for sourceforge bugs 4 and 6.
http://sourceforge.net/p/easygui/bugs/

Created a very cheesy index.html at the top, which has no content other
than the index.

Put all the docs in a documentation folder to keep them separate from
the source.

Still more work as well as checking in the source files to make some of
the docs.
Fix sample: Correct close of main GUI, added images

Fixes sourceforge issue #12 at the end relating to closing the main demo
window.  Added a try/except block around the destroy.  Not the best
strategy, but resolved the reported issue.