The functionality should be identical to vim 7.
In normal mode "[`" takes you to the next lowercase mark, "]`" takes you
to the previous. "['" and "]'" work similarly but just take you to the
line of the mark, not the column.

Closes #1369

Closes #1368

Closes #1374

Closes #1366

Closes #1362

Issue #1364

For line-end/start navigation that stops when a line wraps.

Closes #1364

Closes #1360

Issue #1358

Adds goGroupLeft/Right, delGroupLeft/Right as alternative to word-based
motion/deletion. Binds ctrl-left/right/del/backspace to these commands.

Also makes word and group-based motion stop at line boundaries.

This reverts commit dd919a2b.

The previous solution broke test doc_docKeepsScroll.

- Do not insert closing bracket if a spacechar or closing bracket
  follows cursor
- Do not handle backspace if selection is not empty
- Do not overwrite anything if selection is not empty
- If selection is not empty and open bracket is inserted - surround
  selection with brackets.

Closes #1351

Closes #1349

Closes #1346

When any specified pair is empty, backspacing will also
delete the closing bracket.