Experimentally add JsoupFilter + replace whole filter chain with it

It looks as if jsoup (http://jsoup.org) is what I have been looking for
from the very beginning: a tool which
  - can parse all openbook HTML without pre-filtering or JTidy hacking,
  - has a powerful, concise CSS/JQuery-like selector syntax (no XPath),
  - permits for easy DOM manipulation,
  - is fast,
  - outputs clean, pretty-printed HTML.

Some testing and cleaning up still needs to be done, but for the first
try things are looking pretty nice. I needed to do some logical changes
because jsoup's CSS-like selectors are often equally, but in a few cases
less powerful than XOM's XPath-like ones. Especially the section
removing the feedback forms was changed from a selector-based bulk
removal to a more procedural approach because DOM sibling selection is
not powerful as necessary.
Add member 'title' to Book. Use it in FilterChain and index.htm*.

TOC pages (index.htm*) require special handling for HTML TITLE tags
because there the book title should not been cut off to leave behind a
chapter/page title, but we explicitly want the book title as the page
title there. Instead of specifying a lot of exceptions to clean this up,
I decided to preset the book titles in public member Book.title.

FilterChain as well as BasicFilter and all its subclasses have been
updated to use the new member. In XOMUnclutterFilter.initialiseTitle it
is now used directly if(isTOCFile).
JsoupFilter: use Book.title and fix remaining issues

- Use Book.title in method initialiseTitle, just like the other filters
  do (see previous commit).
- Override more styles for "UNIX guru" book in order to fix remaining
  formatting issues (also synchronised with XOMUnclutterFilter).
- Because CSS-style syntax of jsoup is less powerful than XPath of XOM
  some more procedural solutions for clutter removal are needed:
  methods removeComments, removeNonStandardTopNavigation.
JsoupFilter: rename "XPath" to "Selector", "xPathQuery" to "query"

These were leftovers by copy & paste from XOMUnclutterFilter, the origin
of this class.
For the time being, make old/ne filter chain configurable

In order to get rid of the external dependencies (libs), it would be
desireable to remove the old classes altogether. Maybe the new one needs
some more testing (until now only four books have been tested).
Fix Jsoup.createIndexLink which failed for some books

HTML tag A[href] is not always at the same child index within the
surrounding H2 (or similar) parent node.
JsoupFilter: fix broken tables with key symbols like Alt, Ctrl, F2, Esc

In a few books (e.g. "Excel 2007", page excel2007_24a_001.htm) table
layouts were broken because Selector.IMAGE_BOX_2 was too unspecific,
finding false matches for image boxes to be removed.
Make LoggingFilter work for both XOM and jsoup filter

Both classes JsoupFilter and XOMUnclutterFilter have methods of the same
names and functionalities, so using wildcards and base class name where
applicable enables the missing log messages from XOM filtering also for
jsoup.
Remove old filter chain, get rid of unused libraries (XOM, JTidy)

The new "filter chain" (consisting of JsoupFilter only) is much faster
than the old one which consisted of 4 filters. Removing them makes sense
because the next release will produce a smaller JAR and developers who
wish to change the code also have a simpler setup.
Update CHANGELOG and lib/readme.txt