Invoices plugin

Big update with many new features.

Many thanks to Christian Esbo Agergaard for Danish translation

• Feature #445: Total price without tax/with tax
• Feature #446: German/European invoice template
• Feature #447: Switch of company information for printing
• Feature #466: Add company data to the "Client" menu on new invoice form
• Feature #469: Default currency setting
• Feature #470: Australian dollar currency support
• Feature #471: Highrise and A1 themes support
• Feature #482: Danish currency (DKK)
• Feature #486: Excerpt invoice list view
• Feature #487: Global search by invoice number
• Feature #488: Color invoice statuses
• Bug #480: ActionView::TemplateError (can't convert nil into String) on line #18 of vendor/plugins/redmine_contacts_invoices/app/views/settings/_contacts_invoices.html.erb: