Provide entropy estimate

[fritzophrenic]

The entropy of random-word systems like this can be hard to estimate without knowing the generation method. And, choosing an appropriate number of words for security can be difficult.

I propose an enhancement to show a password strength readout based on the password pattern sequence, that updates automatically as the sequence is changed.

The entropy would be:

lg(number of words in list) * (number of words in passphrase) + lg(number of special characters in list) * (number of extra chars) + (any extra bits to add for capitalization, substitution, etc.)

Estimated strength could be looked up from entropy from the thresholds provided by KeePass documentation.