Minor code cleanup

- remove the extension so you don't need to type it when running the script and so the script is less dependant on being written in bash/sh
- use more heredocs instead of using echo for multiple lines of HTML
- minor indent/whitespace changes

Ignoring whitespace, the output of my version of the script should be the same as yours (given the same initial conditions).

PS: I'm not sure if you can count on being able to use scripting languages other than bash for compatability reasons, but I thought it would be cool to experiment with porting your script to Ruby so I could use ERB for templating the HTML. I have branches for a Ruby version of the script and another version that replaces the script with an ERB file in [my fork](thenickperson/infohgen). Let me know if you have any suggestions.