Don't attempt to wrap each endpoint

Attempting to wrap every endpoint in the GitHub API with a python method is
bound to end in tears. Instead, just provide some simple get/put/post/etc.
helper wrappers around relative URLs and be done with it. This *barely*
increases the amount of code needed at point of use, and dramatically
simplifies the code API code.
Allow specifying scopes on login
Update 'repo' command and add delete action
Update sync-org command
Add 'org' command
Add simple 'browse' command for debugging