Add support for Bitbucket Cloud and Server

[bHacklv]

• filenameSafe now removes query parameters and appends file name to the end of the link to preserve its original file extension.
• Support for Bitbucket Cloud and Server

[nedtwigg]

Thanks, this is a great PR! It has one big problem which is that it adds a new GitAnchorType BRANCH. I think that's a bad idea, but I'm happy to merge it anyway.

But! We should merge Bitbucket support without BRANCH support. Then, after that has been merged, I'd be happy to take a new PR which adds BRANCH support. I just created a new issue for mutable branch support in #24.

If you delete support for BRANCH, it will be quick and easy to get this merged. From there, it's also easy to close out #24 if you still want to.

[nedtwigg]

I made a few tweaks:

• instead of cloudAuth and serverAuth, users can just do auth and we can deal with it ourselves
• using a custom domain implies server(), so we don't need to specify that ourselves
• I made https://bitbucket.org/diffplug/blowdryer

If you're okay with these changes, I'm ready to merge and release.

[bHacklv]

I made a few tweaks:

• instead of cloudAuth and serverAuth, users can just do auth and we can deal with it ourselves
• using a custom domain implies server(), so we don't need to specify that ourselves
• I made https://bitbucket.org/diffplug/blowdryer

If you're okay with these changes, I'm ready to merge and release.

lgtm!

[nedtwigg]

Released in 1.3.0