Version 1.10

- FIX: In a blockwise visual selection with $ to the end of the lines, only the square block from '< to '> is transformed. Need to yank the selection with gvy instead of defining a new selection with the marks, a mistake inherited from the original unimpaired.vim implementation.
- Save and restore the original visual area to avoid clobbering the '< and '> marks and gv by line- and motion mappings.
- Temporarily set g:TextTransformContext to the begin and end of the currently transformed area to offer an extended interface to algorithms.