Makefile; Indentation; Spell-checking

* Add more helpful docs (for me at least :-)) to the Makefile
* Re-default to tab indentation shown as four spaces by default
* Explicitly make Python files use 4-space indentation
* Fix auto-done indentation in mklatex
* Fix spacing between sections in my vimrc
* Add spell-checking to text and HTML files
* Use filetypes more than extensions for KISSing