Template now simply renders a body from a context

--HG--
extra : amend_source : 7112f2330247bae40fbbf77fed92538d9cac9ec8
Support attributes in html, head and body tags when processing content for decoration
Rework decoration middleware and provide an example

--HG--
rename : src/main/java/com/vtence/molecule/middlewares/SiteMesh.java => src/main/java/com/vtence/molecule/middlewares/Layout.java
rename : src/test/java/com/vtence/molecule/middlewares/SiteMeshTest.java => src/test/java/com/vtence/molecule/middlewares/LayoutTest.java