Reorganizes asset file structure

Separates assets into
- Source assets: `assets`
- Compiled assets: `dist`

Edits assets.php to reflect changes

Removes '.min' from filenames

Fixes:
- removes 'clean' from build step.

assets/styles/layouts/_posts.less

@@ -0,0 +1,5 @@
+.hentry header { }
+.hentry time { }
+.hentry .byline { }
+.hentry .entry-content { }
+.hentry footer { }