Standard vectors fix

[QuestofIranon]

This PR applies the fix @maciejhirsz mentioned in #17 (giving co-author credit). It also includes @wigy-opensource-developer's test and reverts back to using the rust only crypto crates.

Fixes #17

[wigy-opensource-developer]

So a Japanese and English mnemonic for the same entropy results in a different seed based on BIP39. That I overlooked as well. Thanks.

[maciejhirsz]

For non-English (English I assume is ok since it's all ASCII anyway) phrases we should really look into encoding the phrases correctly to UTF-8 NKFD (#1).

[QuestofIranon]

This should be ready to merge in, I'll create a second PR for nfkd since it is out of scope. We can discuss changes there since there are some performance hits.

[wigy-opensource-developer]

@steveatinfincia Could you please have a look and consider merging this PR to v0.6, which includes the failing tests in #17 plus the fixes in the seed generation?

[QuestofIranon]

@steveatinfincia Any chance to review this yet?

[wigy-opensource-developer]

Okay, this PR went a bit stale. I keep this fork up-to-date with the fixes for now, but I would be glad to drop it in favor of this upstream.

[maciejhirsz]

I've done the same on my own account, and I've just published that fork on crates, as cargo isn't happy about having a git-based dependency (not even a dev-dependency).

[wigy-opensource-developer]

Hi Stephen @steveatinfincia ! Do you have some plans on how to progress forward with stabilizing the 0.6 release with or without this branch? You have not reacted to this PR for a month now and I am considering to replace dependency to the tiny-bip39 create from Maciej's fork soon if you stay unresponsive. Still thanks a lot for this tool, it was a great help to deal with the complexity this BIP-0039 hides.