Lazy load some gems

[orgads]

Only load them when they are used.

[orgads]

Rebased.

[jaredbeck]

Cross-posting this here, in case it helps someone:

On a related note, removing the top-level requires in #760 may cause issues for some users who fail to require their own dependencies (speaking for a friend 😄 ) For example, if my friend's codebase requires CSV but they fail to specify that dependency in any way, then they will see NameError: uninitialized constant .. CSV after updating httparty to 0.22. This is not a breaking change in httparty, but you might choose, in an abundance of compassion, to mention it in the release notes. 😆
#801 (comment)