fix where the feed generator outputs to, and also output error pages

Signed-off-by: Brian S. Stephan <bss@incorporeal.org>

incorporealcms/markdown.py

@@ -13,18 +13,13 @@ import os
 import re
 
 import markdown
-from jinja2 import Environment, PackageLoader, select_autoescape
 from markupsafe import Markup
 
+from incorporealcms import jinja_env
 from incorporealcms.config import Config
 
 logger = logging.getLogger(__name__)
 
-jinja_env = Environment(
-    loader=PackageLoader('incorporealcms'),
-    autoescape=select_autoescape(),
-)
-
 
 def get_meta_str(md, key):
     """Provide the page's (parsed in Markup obj md) metadata for the specified key, or '' if unset."""