Fix mythmon#145: Rendering errs have wrong line nums

Prepend page content with X newlines, where X is the number of lines
of YAML metadata.  This is to fix issue mythmon#145: reStructuredText rendering
errors have incorrect line numbers.

Note: cherry-picked from 2cd19ed,
re-creating branch to cleanup my git mess.

Conflicts:
	test_site/content/tests/rest_error.rst

test_site/content/tests/rest_error.rst

@@ -12,6 +12,11 @@ filename, just "string"
 The following will trigger a rst rendering error:
     - Should be an extra newline between the
     - first bullet point and the preceeding paragraph
+<<<<<<< HEAD
 
 End of deliberate error document.
+=======
+This is line 15 but wok will report line 11 due to four lines of
+metadata above.
+>>>>>>> 2cd19ed... Prepend page content with X newlines, where X is the number of lines of metadata.  This is to fix issue #145: reStructuredText rendering errors have incorrect line numbers
 

wok/page.py

@@ -103,14 +103,20 @@ def from_file(cls, path, options, engine, renderer=renderers.Plain):
             elif len(splits) == 2:
                 header = splits[0]
                 page.meta = yaml.load(header)
-                page.original = splits[1]
+                # prepend X newlines to original document, where X
+                # is number of lines of metadata (including "---"
+                # delimiter).  Fix for issue #145: rendering error
+                # line numbers are incorrect.
+                newlines = '\n' * (2+header.count('\n'))
+                page.original = newlines + splits[1]
                 page.original_preview = page.meta.get('preview', '')
 
             elif len(splits) >= 3:
                 header = splits[0]
                 page.meta = {}
-                page.original = '\n'.join(splits[1:])
-                page.original_preview = splits[1]
+                newlines = '\n' * (2+header.count('\n'))
+                page.original = newlines + '\n'.join(splits[1:])
+                page.original_preview = newlines + splits[1]
                 page.meta.update(yaml.load(header))
                 logging.debug('Got preview')