Cleaning up some of the Instagram code.

Adding `if` braces and cleaning up commenting style.
Removing unnecessary Google maps url from Instagram.
Cleaning up Instagram URL generation.
Added better checking for empty Instagram pagination.

If Instagram douesn't have pagination info then there is still a
pagination property in the reply, but it has no properties inside of it.
Added better checking so that we don't get PHP warnings when there is no
pagination info.
Fixed incorrect reference to response data when getting user id.

0b38e2a introduced a breaking change with the format in which
`do_request()` returns data in the Instagram service. The `get_user_id()`
function never got updated with this change so it would error out when
called.