Parse descript.ion file for metainformation

This patch add a 3 new options:
description: set descript.ion filename which is ".descript.ion" by default
name: you can customize the displayed name
title: you can customize the title (browser show up in a tooltip)

In name and title you can use the following tokens:
%f -> filename with extension e.g. LICENSE.txt,
%b -> filename without extension e.g. LICENSE
%e -> extension e.g. txt,
%m -> metainfo (read from description)
%mf -> metainfo, or if no metainfo than filename
%mb -> metainfo or basename
%lf, %lb, %le, %mlf, %mlb -> use lovercase filename, basename, extension e.g. license.txt
%uf, %ub, %ue, %muf, %mub -> use uppercase e.g. LICENSE.TXT

descript.ion files are standard BBS descript.ion files:

The format of descript.ion files is very simple. It is a text file, with lines in the format of:
<filename><single space><arbitrary description>
For example:
DESCRIPT.ION Mapping of file names to descriptions
It is now possible for filenames to have spaces in them, so the format has evolved a little to additionally include:
<“quoted filename”><single space><arbitrary description>