Cache search results so clicking the back button after clicking on a search result does not execute the search again

Created by: limitedmage

Flow:

1. Execute a search and wait for results
2. Click a result.
3. Read the result, realize it's not what you're looking for. Click back button to back to results.

Current behavior:

Search runs again and you have to wait for results again, which depending on the search may take a long time (eg. unindexed searches). Because we don't have consistent sorting, results may not be in the same order as before.

Suggested behavior:

Results for the last query are cached so going back to the results page shows the same results. This should only happen if the search completed successfully.