config option for each website to set an other currency than that set in the server-config
while we are it, we can add the very similar "Number format" setting to allow 3,000,000 VS current behavior 3000000
Moved the number format preference to its own ticket at #1254
(In [2020]) Fixes #1001 Adding currency setting per website
Defaulting currency to USD for all existing websites
Simplifying website admin screen by rolling all settings into the same form (still using ajax)
Adding SitesManager and UsersManager to the list of hidden plugins
Slightly refactored printing money values to accomodate per website preference