Add separate setting for approval mails.

Add own generic setup profile for upgrades to make sure no existing values are overwritten.
Fix conditions for sending mails.
Merge remote-tracking branch 'origin/deif-add-separate-approval-mail-setting'

Conflicts:
	seantis/reservation/mail.py
	seantis/reservation/profiles/default/metadata.xml
	seantis/reservation/profiles/default/registry.xml
	seantis/reservation/resource.py
	seantis/reservation/upgrades/upgrades.py
	seantis/reservation/upgrades/upgrades.zcml
Fix tests.
Use correct update method.
Merge pull request #45 from 4teamwork/master

Add separate setting for approval mails.