Revert "add lxml dep"

requirements.txt

@@ -15,6 +15,5 @@ PyYAML==3.12
 redis==2.10.6
 six==1.11.0
 tmx==1.9.1
-lxml==4.2.5
 git+https://github.com/buxx/synergine2.git@master
 git+https://github.com/buxx/cocos.git@tileset