Purchase order written to table
Purchase order receipts (for depo request), purchases logged correctly
Purchase order payment structure
Merge branch 'purchase' into dev

Conflicts:
	app/js/app.js
Merge branch 'dev' of https://github.com/IMA-WorldHealth/Kapok into dev
Notes and schema from meeting
Merge branch 'dev' of https://github.com/IMA-WorldHealth/Kapok into dev