Deal explicitely with parentless automatic styles

also stop assuming that automatic styles can have other automatic styles
as parent
Built-in default values for optional attrs fo:text-indent and text:min-label-distance
Fix StepsCache's getNodeId() to always return a string
Fix getAttributeNS related comment in RelaxNG2's validateAttribute()
Make parsing methods of odf.OdfUtils deal with undefined & null values
Fix exception on  masterPageName being null in odf.StyleCache.masterPage()
Do not pass null to odf.Formatting.getMasterPageElement()
deal with possible not existing xlink:href attribute in OdfUtils.getHyperlinkTarget

as this is in a public method with no other check if the passed element
is a proper <text:a> element, better be safe then sorry
Make parsing methods of odf.StyleParseUtils deal with undefined & null values
attribute style:display-name is only optional, use style:name as fallback for display
Make odf.StyleParseUtils' lengthInPx() deal with undefined & null values
Merge pull request #564 from kossebau/fixGetAttributeNSUse

Fix getAttributeNS usages
Remove unused webodf/tests/test_odt directory

This directory has never been used, even within the commit that added it
Remove try-catch blocks that immediately rethrow the caught exception

These effectively act as slightly expensive no-ops. There is no need
for them to be present.
Log additional information if a stylesheet rule fails to insert
Add test document demonstrating list escape character issues
Escape list prefix, suffix and bullet chars in the CSS rules

Various browser cope differently with unescaped characters in a CSS
content block, though all browsers agree it is a bad thing. WebKit
will throw an error, Chrome & FF will "guess" where the rule ends
(and usually get it wrong).

This patch does 2 things to fix this:
- Consistently use double-quotes to quote strings
- Escape backspace and double-quote chars in the CSS-related content

The vast amount of testing code is primarily creating a string tokenizer
able to parse out the displayed text across Chrome/WebKit + FF. As there
is no simple way to get the "rendered text" from a pseudo-element, a lot
of code is required to compute this. There are tests included for the
hand-rolled tokenizer as well to ensure proper function.

No tests have been added for OdfCanvas, as the existing list logic in
here is destined (sooner rather than later) to be merged into the newer
list CSS translation class.
Add workarounds for qtruntimetest's version of WebKit

Content needs to be on a new line if it contains slashes due to a bug in
older versions of webkit. E.g., the one used in the qt runtime tests.
See https://bugs.webkit.org/show_bug.cgi?id=35010

In addition, asking for the value of a content block that contains a
counter returns a strange counter string such as "counter(-879878e564)".
I can't find a bug report for this, but it only occurs inside the qt
runtime tests.