Try double site parameter; no success
Add siteconfig for Yahoo

This initial version does not support Yahoo's second sign in verification or password re-input (i.e., the password request displayed before Yahoo allows user to modify account settings). Cf. https://github.com/waltzio/waltz/pull/192
Merge branch 'site-Yahoo' of github.com:lolux/waltz into lolux-site-Yahoo
fixes broken wells fargo regex, fixes #314