sync parameters to API v3

[jamesturk]

API v3 parameters differ from API v1, and there are still places that this could be fixed in the code

• bill search
• bill get
• metadata
• get_organizations
• search_legislators
• get_legislator
• locate_legislators
• search_districts

the v3 docs are pretty good & 100% complete by virtue of being autogenerated, https://v3.openstates.org/ bringing the library in line with those would be a great task for someone interesting in getting a bit more involved