Update edit.html

Redrafts tooltips.
Update home.html

Tooltip redrafts.
Update edit.html

Copy redrafts.
Update pending-single.html

Copy redrafts.
Update issue-by-email.html

Copy edits.
Update help.js

Adds sharing, issue by email and other general updates.
Update help.js

Removes references to signing up for private beta.
Update help.js

Clarifying private beta language.
Merge pull request #427 from mozilla/help-updates

Help updates