Refactor Blade implementation (again), closes #1769 (#1777)

* Squash bugs, reorganize, etc.
* Use `get_body_class()` to apply filters on template data
* Use `PHP_INT_MAX` as priority for `template_include` filter

composer.json

@@ -31,8 +31,7 @@
   "require": {
     "php": ">=5.6.4",
     "composer/installers": "~1.0",
-    "illuminate/view": "~5.3.0",
-    "jenssegers/blade": "dev-master#59ba2cc"
+    "illuminate/view": "~5.3.0"
   },
   "require-dev": {
     "squizlabs/php_codesniffer": "^2.5.1",