pass isTest & lineitems into processContribution

further refactoring to pass more params into smaller functions to make fixing membership line items doable

fix on previous refactor

Conflicts:
	CRM/Member/Form/Membership.php
comment fixes & spelling
CRM-14197 towards refactoring form specific actions back onto the form as part of
figuring out how to set membership entity id on line item (preliminary simplication
Move the create CMS user onto the form function

move create CMS user back onto form & encourage passing of membership id to renewmembership function

create user AFTER processing membership in case if fails & all is lost
further refactoring to pass more params into smaller functions to make fixing membership line items doable
clarify creation of creating a separate membership contribution
param fix & clarify object to pass to updateRecurmembership fn
declare membershipContributionID & use that
remove  param
don't check for empty on  - would have had an error
remove unrequired param
set membershipContribution directly as required
remove minor code duplication, ensure  set to form value
minor cleanups
remove invalid return & unused parameter
clarify isSeparatePayment into it's own function
refactor processing of secondary transaction into separate function
evaluate form contribution TypeID on form function
refactor creation of membership_payment records into shared function
use try catch rather than passing errors as a reference