increased padding on image buttons on v21 to match material guidelines

src/main/res/layout/activity_edit_account.xml

@@ -337,7 +337,7 @@
                         android:layout_alignParentRight="true"
                         android:layout_centerVertical="true"
                         android:background="?android:selectableItemBackground"
-                        android:padding="8dp"
+                        android:padding="@dimen/image_button_padding"
                         android:src="?attr/icon_copy"
                         android:visibility="visible"
                         android:contentDescription="@string/copy_otr_clipboard_description"/>

src/main/res/layout/activity_muc_details.xml

@@ -75,7 +75,7 @@
 					android:layout_alignParentRight="true"
 					android:layout_centerVertical="true"
 					android:background="?android:selectableItemBackground"
-					android:padding="8dp"
+					android:padding="@dimen/image_button_padding"
 					android:src="?attr/icon_edit_dark"/>
 			</RelativeLayout>
 
@@ -102,7 +102,7 @@
 				android:layout_alignParentRight="true"
 				android:layout_centerVertical="true"
 				android:background="?android:selectableItemBackground"
-				android:padding="8dp"
+				android:padding="@dimen/image_button_padding"
 				android:src="?attr/icon_settings"/>
 				</RelativeLayout>
 

src/main/res/layout/contact_key.xml

@@ -34,7 +34,7 @@
         android:layout_alignParentRight="true"
         android:layout_centerVertical="true"
         android:background="?android:selectableItemBackground"
-        android:padding="8dp"
+        android:padding="@dimen/image_button_padding"
         android:src="?attr/icon_remove"
         android:visibility="invisible" />
 

src/main/res/values-v21/dimens.xml

@@ -1,4 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
 	<dimen name="elv_undo_bottom_offset">63dp</dimen> <!-- 48dp + 15dp -->
+	<dimen name="image_button_padding">12dp</dimen>
 </resources>

src/main/res/values/dimens.xml

@@ -4,4 +4,5 @@
 	<dimen name="activity_vertical_margin">8dp</dimen>
 	<dimen name="infocard_padding">16dp</dimen>
 	<dimen name="conversations_overview_width">288dp</dimen>
+	<dimen name="image_button_padding">8dp</dimen>
 </resources>