Accelerator keys for most recently used searches.

[cheater]

After implementing #25, add accelerator keys for the last 5 searches to q w e r t.

For example, to access the second-last used search, you would press m, then w; or after the feature request #24 is implemented, it could be d, then w.

Make it possible to disable this feature.

Make it possible to change the keys from qwert to something else.