Merge branch 'flow' of flow/Mercury-IM into master

README.md

@@ -12,7 +12,7 @@
 ```
 git clone <project-url>
 cd <project-directory>
-git submodule init && git submodule update
+git submodule update --init --recursive
 gradle assembleDebug
 ```
 
@@ -21,4 +21,4 @@ gradle assembleDebug
 * I want to develop, but lots of `org.jivesoftware.smackx.*` classes cannot be found!
   * You forgot to type `git submodule init && git submodule update` as mentioned above
 * I'm missing `org.mercury_im.messenger.persistence.requery.*` classes???
-  * In Android Studio select the `persistence-requery` module and then click "Build -> Make Module 'persistence-requery'".
+  * In Android Studio select the `persistence-requery` module and then click "Build -> Make Module 'persistence-requery'".

build.gradle

@@ -37,7 +37,6 @@ allprojects {
         // Exclude XmlPullParser from Smack dependencies, as its now provided by Android
         // https://stackoverflow.com/questions/48488563/gradle-xpp3-error/48746294#48746294
         all {
-            exclude group: 'xpp3', module: 'xpp3'
             exclude group: 'xpp3', module: 'xpp3_min'
         }
     }