port onchanges to API 8.0 to fix #22
Add a second search when no agreement is found

This restore former warning message when we can find an agreement with
not enough quantities
This allow to find and finish the framework agreement almost finished.
As it is preferable to finish agreements completely instead of
contracting new ones and be left with multiple remainings of agreements.
add a constraint on delivery date to forbid asking goods before requisition date
adapt tests to set requisition date
adapt tests of logistic_budget due to new constraint on date in logistic_requisition
manage proper copy of LR

duplicate LR lines but not the sources.
fix issue in cost estimate creation

populate the sourced_by field of the SO line with the PO line doing the
sourcing
fix error using self in api.multi method
fix UnboundLocalError
more details in test
prevent copy of cancel reason and cost_estimate_id
fix: don't set code on PO generated from agreement

When generating a purchase order from a framework agreement, the code
should be auto-generated from the sequence, and not be equal to the code
of the logistic requisition.

This bug was already fixed on v7 by Nicolas Bessi. Then for some reason,
while porting to v8 I re-enabled a commented out line bringing that
back.

Now it is deleted for good.
Merge pull request #24 from gurneyalex/8.0-fix_LR_issues

manage proper copy of LR
Merge pull request #19 from yvaucher/8.0-constraint-on-delivery-date

add constraint on delivery date to forbid asking goods before requisition
update the test to fail without the fix

closes lepistone#1
remove currency from LRS: breaks creation
Add an option to set a SO as cost estimate only and create a workflow that will change the Cost Estimate only once it has been sent by mail.
Hide button Confirm Cost Estimate when Cost estimate only is active
Add a filter to see all Cost Estimates Only
Filter tree view to show Done cost estimate only in Cost Estimates