Don't auto activate Verification Tools if conflict

If Yoast’s plugins are active, they’re already providing this
functionality, so we don’t need to auto-activate ours.
Add in a clarification / caveat for debug mode.
Whitespace oops
Setting version to beta3
Update jetpack.pot

Running `grunt makepot`. — unsure about the reason for the comment
changes since the last pass.  @lezama — thoughts?