Add helper function to update an option
Break up unit tests and add for new function
Merge branch 'option-update-helper' of https://github.com/mAAdhaTTah/CMB2 into mAAdhaTTah-option-update-helper
update .pot for new line numbers
Remove unecessary $resave variable.
Update docblock descriptions to be more rational
Merge branch 'mAAdhaTTah-option-update-helper', "Add helper function to update an option". Props @mAAdhaTTah.