Find a solution to the "repetition of history" problem for manually re-entered hashes.

[nathanhammond]

There is a possible fail state if a person manually re-enters a previously existing hash: it will be appended to the end of the history, but the stack pointer will be adjusted to the first time it appeared in the history stack. This creates a state where you've come to the page "fresh" but are loading in the old state.

PARTIAL SOLUTION: Watch for changes in window.history.length. Compare these to the initial length when arriving at the page and the number of items on the site's stack.

Success Scenarios:
1. A manually re-entered hash that matches the current one won't trigger an event or change the length (click location bar, press enter, no change).
2. A manually re-entered hash that doesn't match the current hash changes window.history.length, and is catchable.

Fail Scenarios:
1. The user is exactly one spot deep in the browser history stack. The length does not change because it pops all future events off the stack and adds a new one immediately.