are completely skipped, rather than being treated as blank lines
(and then subject to the 'skip_blanks' flag).  This allows us
to process old-style Setup files, which rely on
  hello \\
  # boo!
  there
coming out as "hello there".

Fixed precendence bug that meant setting skip_blanks to false didn't work
under some circumstances.

Factored the guts of 'warn()' out to 'gen_error()', and added the
'error()' method (trivial thanks to the refactoring).

Dropped the 'collapse_ws' option and replaced it with 'collapse_join' --
it's *much* faster (no 're.sub()') and this is the reason I really added
'collapse_ws', ie. to remove leading whitespace from a line being joined
to the previous line.

Slightly improved the code for dealing with newline on a comment line,
  and for stripping whitespace.

  - did away with 'comment_re' option -- it's just not that simple anymore
  - heavily revised the main logic in 'readline()' to accomodate this
Beefed up 'warn()': 'line' can be list or tuple, and 'msg' is
  automatically converted to a string.

works on non-seekable file-like objects, such as URLs.  (Oops.)

ProcessHierarchy's changes to support reading from a remote URL in
ProcessDatabase).

files with (optional) comment stripping, blank line skipping, whitespace
removal, and line joining with trailing backslashes.