Removed dependency from Twee on wxWidgets

Twee is a command line tool, so it shouldn't depend on a GUI toolkit.
However, the "tweelexer" module contained both GUI functionality and
essential non-GUI definitions. Solved this by splitting off the regex
definitions into the new module "tweeregex" and make Twee import that
instead.
Merge pull request #127 from mthuurne/twee_no_wx

TweeRegex module
twee: Removed HTML merge feature

The feature is not useful for story authors.
Read this forum thread for some background:
  http://twinery.org/forum/index.php/topic,1463.0.html
StorySettings dialog scrollbars

* Added support for scrollbars in the StorySettings dialog, in case
custom story formats wish to add a lot of settings that necessitate a
longer window.
* Removed the "IE hack" from monospacedByLineHelper, after confirming
that it is not needed in IE 8.
twee: Fix preservation of passage order

This feature was introduced in 4a038af9, but I broke it in bba0e147
when I did the tabs to spaces conversion on the wrong version of the
"twee" script (the part in tiddlywiki.py survived).
Fixed StoryIncludes on OS X

buildIncludes() wasn't taking the story's path into account for relative filenames.
Merge pull request #129 from mthuurne/twee_remove_merge

twee: Removed HTML merge feature
Merge pull request #130 from mthuurne/fix_passage_order

Fix preservation of passage order in Twee