Add tests on gh-12
Fix characterwise deletion to target a right text

Characterwise deletion did not target a right region if 'ignorecase' is
enabled.  For example, `"*dw` was treated as `"*dd`, and `vb"&d` was
treated as `vb"&D`.
Refactor - Fix comparisons to be case-sensitive
Merge branch 'fix-deletion-behavior'

Close gh-11.
Close gh-12.
Add tests on gh-3
Fix Y in characterwise Visual mode to act linewise
Merge branch 'fix-yank-behavior'

Close gh-3.