Update docs and German translation

doc/development/api/payment.rst

@@ -102,6 +102,8 @@ The provider class
 
    .. automethod:: order_control_refund_perform
 
+   .. automethod:: is_implicit
+
 
 Additional views
 ----------------

doc/user/events/taxes.rst

@@ -100,6 +100,16 @@ taxes" at the end of the page.
           errors of usually up to one cent from the intended price. This is unavoidable due to the
           flexible nature in which prices are being calculated.
 
+Custom tax rules
+----------------
+
+If you have very special requirements for the conditions in which VAT will or will not be charged, you can use the
+"Custom tax rules" section instead of the options listed above. Here, you can create a set of rules consisting of
+conditions (i.e. a country or a type of customer) and actions (i.e. do or do not charge VAT).
+
+The rules will then be checked from top to bottom and the first matching rule will be used to decide if VAT will be
+charged to the user.
+
 Taxation of payment fees
 ------------------------
 

src/pretix/locale/de/LC_MESSAGES/djangojs.po

@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2018-02-26 09:47+0000\n"
+"POT-Creation-Date: 2018-03-03 20:06+0000\n"
 "PO-Revision-Date: 2018-02-03 16:56+0100\n"
 "Last-Translator: Raphael Michel <michel@rami.io>\n"
 "Language-Team: \n"

src/pretix/locale/de_Informal/LC_MESSAGES/djangojs.po

@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2018-02-26 09:47+0000\n"
+"POT-Creation-Date: 2018-03-03 20:06+0000\n"
 "PO-Revision-Date: 2018-02-03 16:56+0100\n"
 "Last-Translator: Raphael Michel <michel@rami.io>\n"
 "Language-Team: \n"