Cleanup <include/> and etc. in keyboard XML

* Remove keyXPos and keyWidth from key_*.xml and make it more generic.
* Add keyXPos and keyWidth to <include/> generalized key_*.xml.
* Remove zero width <Spacer/> and fold into successive <include/>.

Change-Id: I4b5c02a165ba0bc9ef8741be0b4938c1efaf5e27
diff --git a/java/res/xml/row_qwerty4.xml b/java/res/xml/row_qwerty4.xml
index 361a2c3..6780349 100644
--- a/java/res/xml/row_qwerty4.xml
+++ b/java/res/xml/row_qwerty4.xml
@@ -30,6 +30,7 @@
         <include
             latin:keyboardLayout="@xml/key_f1" />
         <include
+            latin:keyXPos="25%p"
             latin:keyboardLayout="@xml/key_space" />
         <Key
             latin:keyStyle="punctuationKeyStyle" />