Fixing Exponential newWidget distance issue

line 263,  passing Pixel coordinates to newWidget() instead of logical to get the correct starting position.
Syntax highlighting improvements and other fixes

Back macro:

* Now it accepts variables for the steps parameter and the

tweelexer.py:

* Now recognises mixed-case and uppercase <html> tags

* /% %/ comments, {{{ }}} monospacing, @@ @@ errors, and

* bold, italic and underline now apply these styles to the text, instead
of just greening it.

* Now handles nested syntax correctly.

* Now handles inline external links correctly.

* Now colours the link and image parts of inline images separately.

* Now colours text inside <<silently>> macros correctly.

Wikifier.formatHelpers:

* Tidied up the regexes for html and image.

* The < and > options for inline images now use CSS float attributes
instead of the deprecated HTML align attributes.

* The title text option for inline images now alters the alt attribute
as well.