Possibly switch to Bitbucket API v2

[jeffwidman]

Bitbucket rolled out API v2, need to check whether we should switch or not:
https://blog.bitbucket.org/2013/11/12/api-2-0-new-function-and-enhanced-usability/

In general, it's obviously better to be using what BB is most excited about, but it's not clear that BB plans to expand their v2 api to the point of eventually killing their v1 api.

A brief exploring of the API looks like there's some endpoints that could fix #16, #32, #8

[jeffwidman]

So I looked at this some more, while there's no clearly documented endpoint, it does exist:

https://bitbucket.org/api/2.0/repositories/zzzeek/sqlalchemy/issues/?sort=id&page=10&pagelen=2

as partially documented here: https://confluence.atlassian.com/bitbucket/version-2-423626329.html

Note that pagelen can be as high as 100 vs v1 of the API is only 50.

Would probably want to rethink how to traverse the API--it returns next/previous/entity links for everything, so should use that rather than hardcoding next page links.

There is no start param that I could find, which affects #32.

Overall, I'm not seeing any real benefits to switching to v2, so will keep this on hold for now.