Handle some orientation changes manually

Currently most activities get destroyed/recreated when rotating the
device. This commit prevents this from happening where it is not
necessary.

The most obvious improvements are:

 * The options menu in the EditAccountActivity does not disappear when
   rotating the device.

 * CSI inactive/active states are no longer sent on every rotate.

src/main/AndroidManifest.xml

@@ -39,6 +39,7 @@
         <activity
             android:name=".ui.ConversationActivity"
             android:label="@string/app_name"
+            android:configChanges="orientation|screenSize"
             android:launchMode="singleTask"
             android:windowSoftInputMode="stateHidden">
             <intent-filter>
@@ -95,14 +96,17 @@
             android:launchMode="singleTask"/>
         <activity
             android:name=".ui.EditAccountActivity"
+            android:configChanges="orientation|screenSize"
             android:launchMode="singleTask"
             android:windowSoftInputMode="stateHidden|adjustResize"/>
         <activity
             android:name=".ui.ConferenceDetailsActivity"
+            android:configChanges="orientation|screenSize"
             android:label="@string/title_activity_conference_details"
             android:windowSoftInputMode="stateHidden"/>
         <activity
             android:name=".ui.ContactDetailsActivity"
+            android:configChanges="orientation|screenSize"
             android:label="@string/title_activity_contact_details"
             android:windowSoftInputMode="stateHidden"/>
         <activity