accounting: update account list cache when modifying/validating accounts
Using a cache cookie that is incremented each time an account is added or modified, we can keep an (almost) up to date list of accounts in the UI.
Fixes #20170221-1812E21
Using a cache cookie that is incremented each time an account is added or modified, we can keep an (almost) up to date list of accounts in the UI.
Fixes #20170221-1812E21