the indentation of a comment block to be ignored when reformatting the
block, leading to overly long reformatted lines (too wide by an amount
equal to the indentation width).  Looks like a typo in the original
patch, a 1-character repair.

Rev 1.10 (string methods)

EditorWindow.py:

+ Added get_tabwidth & set_tabwidth "virtual text" methods, that get/set the
widget's view of what a tab means.

+ Moved TK_TABWIDTH_DEFAULT here from AutoIndent.

+ Renamed Mark's get_selection_index to get_selection_indices (sorry, Mark,
but the name was plain wrong <wink>).

FormatParagraph.py:  renamed use of get_selection_index.

AutoIndent.py:

+ Moved TK_TABWIDTH_DEFAULT to EditorWindow.

+ Rewrote set_indentation_params to use new VTW get/set_tabwidth methods.

+ Changed smart_backspace_event to delete whitespace back to closest
preceding virtual tab stop or real character (note that this may require
inserting characters if backspacing over a tab!).

+ Nuked almost references to the selection tag, in favor of using
get_selection_indices.  The sole exception is in set_region, for which no
"set_selection" abstraction has yet been agreed upon.

+ Had too much fun using the spiffy new features of the format-paragraph
cmd.

Read the comments (which I reformatted using the new feature :-)
for some limitations.

I'm still unsure, but couldn't stand the virtual event trickery so tried a
different sin (adding undo_block_start/stop methods to the Text instance in
EditorWindow.py).  Like it or not, it's efficient and works <wink>.  Better
idea?

Give the attached a whirl.  Even if you hate the implementation, I think
you'll like the results.  Think I caught all the "block edit" cmds,
including Format Paragraph, plus subtler ones involving smart indents and
backspacing.

fix find_paragraph when at start of file.