Fixed displaying of long titles in PassageFrame
<<choice>> and either() changes

* <<choice>>, <<button>> and <<textinput>> no longer incorrectly convert
Twine operators in the text of the provided link to Javascript
operators.
* either() may now accept a single array as an argument, and will
apply() that array to itself. This allows you to save a bunch of
either() arguments in an array variable, and call either() with it in
many places.
Merge pull request #126 from greyelf/i013_passage_title_fix

PassageFrame title field hides starting characters
Merge pull request #125 from mthuurne/twee_cleanup

Twee cleanup
Find links in SugarCube-style <<click>> and <<link>> macros

The <<link>> syntax is ambiguous in the 2-argument case. I checked the
SugarCube source and if the last argument is a known action keyword,
it is treated as an action, otherwise it is treated as a location.

Since these macros are SugarCube-specific, this code should probably
be moved into the header-specific Python module, once that lands.
Add special passage names and tags for SugarCube

This is a temporary solution; it would be better to make the header-
specific Python module register these.