Add ~ as safe field for connection build_url_base

[bpicolo]

Without this key signing through Amazon will actually fail for any keys with a ~ inside of them. (I.E. key.generate_url -> connection.generate_url returns a URL that isn't validly signed).

[bpicolo]

I guess that description was bad. Let me explain better.

~ is a valid character in a URL. When you sign the UTF8 encoded version, the equivalent link with a ~ is not validly signed. A browser will automatically convert (%7E I think it is) to ~ for the request, so you will not hit a validly signed link.

At least, that's what it seems like to me. Then again, CURL seems to fail as well, so it might just be that signing with %7E will never be valid.

[danielgtaylor]

Can you please add a unit test covering this use case? We need to make sure not to break both existing behavior and to not break this new behavior in the future.

[bpicolo]

Sure.

Would it be possible to get a little feedback on this, I suppose? I'm not particularly experienced with the boto library. Offhand, does what I described seem accurate?