ringtones: add default ringtone option

This commit adds a button to choose between a default and a custom ringtone.
Default.wav was compressed.

Change-Id: I4d866b837d877fe9220f20d900ffee5b290745be
Tuleap: #1117
diff --git a/ring-android/app/src/main/res/values/strings_account.xml b/ring-android/app/src/main/res/values/strings_account.xml
index bc587f6..3d3137e 100644
--- a/ring-android/app/src/main/res/values/strings_account.xml
+++ b/ring-android/app/src/main/res/values/strings_account.xml
@@ -80,6 +80,7 @@
     <string name="account_ringtone_label">Ringtones</string>
     <string name="account_ringtone_enabled_label">Activate ringtones</string>
     <string name="account_ringtone_path_label">Ringtone path</string>
+    <string name="account_ringtone_custom_label">Use custom ringtone</string>
 
     <!-- Video Details -->
     <string name="account_video_label">Video</string>