documenting two new options

Configuration.md

@@ -52,6 +52,8 @@ Preselect the burn-after-reading feature by default, defaults to false.
 
 The `default` option in the `[expire]` section controls, which expire value is selected by default. Make sure the value exists in the section `[expire_options]`.
 
+Setting the `clone` option to false will hide the clone button in expiring pastes. Note that this only hides the button, simply copying the paste into a new one is still possible.
+
 In `[expire_options]` you can define the expiration options. These define the lifetime of a newly created paste in seconds. The `[expire_labels]` option found in version 0.20 is deprecated and will no longer be required in version 0.21, instead the labels are generated based on the keys in the `[expire_options]`.
 
 Using a value of 0 for the seconds means to never expire this post. Remove this line from the default configuration if you want to enforce that all pastes expire eventually in your system. But be aware that changing this setting only affects newly created pastes.
@@ -74,12 +76,21 @@ The option `dir` controls where the lock file is stored. Note that this director
 
 The base64.js library version, defaults to `2.1.9`. Use `1.7` if you are upgrading from a ZeroBin Alpha 0.19 installation for compatibility with your existing pastes.
 
-### languageselection
+### languageselection / languagedefault
 
-By default ZeroBin tries to detect the browser language of the visitors if such a HTTP header is sent and falls back to English language if no such header is present or no matching translation was found.
+By default ZeroBin tries to detect the browser language of the visitors if such a HTTP header is sent and falls back to English language or to the one selected in `languagedefault`, if no such header is present or no matching translation was found.
 
 Optionally `languageselection` enables drop down can be enabled. It is disabled by default, as it makes use of a session cookie named "lang" to persist the selected language between calls. It is deleted when the browser is closed.
 
+When `languageselection` is disabled and `languagedefault` is set, then the `languagedefault` will be the only language used and this will be communicated to the browser via the session cookie named "lang". Here is a matrix of the possible effects of the language configurations:
+
+`languageselection` | `languagedefault` | cookie  | behaviour
+--------------------|-------------------|---------|----------
+false               | not set           | not set | uses browser language, if possible
+false               | set, i.e. to "en" | set     | will always be in the `languagedefault` language
+true                | not set           | set     | uses browser language or the one last selected and stores it in the cookie
+true                | set, i.e. to "fr" | set     | uses browser language or the one last selected and stores it in the cookie and uses "fr" as the fallback for unknown browser languages
+
 ### model
 
 The sections `[model]` and `[model_options]` control how your pastes are stored. Currently ZeroBin stores its pastes as flat files by default (`[model]` section, `class = zerobin_data`) and the option `dir` in the section `[model_options]` tells it in what folder to store them. Note that this directory needs to be writable for the process running PHP (i.e. your webserver, FPM or CGI process).