Fix use of browser history

[rgrempel]

This will fix #38.

One problem was the a [href "#"] [onClick ...] ... the href essentially contradicts what the onClick wants to do. One would either have to use the correct href (and have no onClick), or (better) have no href and just rely on the onClick.

I'm presuming the purpose of the href "#" is to ensure that the cursor changes to a pointer, so I put that in manually.

I suppose we do lose the ":visited" styling this way (which we could get by using the correct href) -- in cases where distinct styling for ":visited" was critical, one could use the correct href and leave off the onClick.

The other issue relates to how to handle "default" URLs (that is, what page do we want to show for an empty hash). I've made some changes here that seem to improve that. I should work on this a bit and see if I can make it nicer in elm-route-url -- there is some interaction here between what elm-lang/navigation does and and what elm-route-url does and what evancz/url-parser does, and I'm not absolutely sure what the best approach is.

[rgrempel]

This is ready for review, @amitaibu

[amitaibu]

Maybe we can try to use href="javascript:;"?

[rgrempel]

But in that case, I don't understand what the purpose of having an href is? You wouldn't get any useful :visited styling from it. If the purpose is to get a cursor: pointer, then it actually seems better to me to do that directly, rather than in an obscure manner.

[amitaibu]

Great, thanks.